Three pots, three plans: £250, £600 and £1,200
Three test batches of £250, £600 and £1,200 ran between 2026-04-20 and 2026-09-12, holding 5, 13 and 26 lines. Landed cost per line came to £45.03, £42.53 and £42.57 respectively (Recorded, 44 lines across three batches).
The headline is uncomfortable for anyone planning to scale: quadrupling the pot from £250 to £1,200 moved the unit cost by £2.46, and the last doubling moved it by 4 pence. Volume helped, then stopped helping.
1. Fix the pot you can afford to leave in the warehouse. 2. Choose the number of lines that pot supports. 3. Price every line from its landed figure. 4. Re-measure before adding money to the next pot.
Add a fourth figure to the pot before choosing it: how long you can leave the money out. A £250 batch that clears in six weeks is a different proposition from a £1,200 batch that takes five months, even when the unit cost of the larger batch is lower.
The three pots were chosen to answer one question: does spending more lower the unit cost enough to justify the extra exposure. £250 was the smallest batch that could fill two parcels, £600 was the smallest that could carry two categories, and £1,200 was twice that again, so the comparison isolates scale rather than anything about the goods themselves.
Composition mattered as much as size. The £250 pot held five lines of one category with two sizes each, the £600 pot held thirteen lines across two categories with four to five sizes each, and the £1,200 pot doubled the middle one without widening the size spread, which is why its unit cost barely moved.
Five lines in one category: the smallest pot and its two parcels
Five lines in one category cost £171.20 in goods, £11.40 in domestic freight, £10.96 in service fee, £26.60 in shipping across two parcels and £5.00 in QC photography, which is £225.16 landed (Recorded, one batch).
One category kept the sizing spread narrow, and two parcels kept the opening rungs to two. The per-line average of £45.03 is the highest of the three pots, which is the price of a small batch rather than a mistake.
A single category also makes the pricing easy. When every line is a hoodie in three sizes, one landed figure per size band is enough to price the whole batch.
Count the parcels before counting the lines. Two parcels carried the five lines of the first batch, which kept two opening rungs in play, and the same five lines split across three parcels would have cost an extra £6.80 before anything else changed.
Keep the first batch to one size range as well as one category. Five lines in three sizes is a batch you can price from a single landed figure per size band, and that simplicity is worth more on a first run than a wider spread would be.
Thirteen lines, two categories and the first real sizing spread
Thirteen lines across two categories cost £412.60 in goods, £27.80 in domestic freight, £26.42 in service fee, £73.60 in shipping across four parcels and £12.50 in QC, giving £552.92 landed and £42.53 per line (Recorded, one batch).
The second category is where the arithmetic gets harder. A sizing spread means some lines sit unsold for months, and an unsold line has already consumed its freight, its QC charge and its share of a first-kilogram band.
1. Sort the batch by category. 2. Count the sizes in each. 3. Price the slow sizes at a higher multiple. 4. Keep the fastest size as the anchor for the rest of the batch.
Watch the slow sizes rather than the average. Two of the thirteen lines in the middle batch took eleven weeks to move, and each of them carried its freight, its QC charge and its share of an opening rung through every one of those weeks.
Price the second category from its own landed figures rather than from the batch average. £42.53 per line across two categories can hide one category at £36.00 and another at £49.00, and a single price for both would lose money on half the batch.
The sizing spread is what makes a second category expensive. Thirteen lines across two categories means four or five sizes per line, and every size that does not move carries its freight and its QC charge through the whole quarter, which is why the middle pot returned less per line than the smallest one on some individual lines.
The £1,200 pot: where extra money stops lowering the unit cost
Twenty-six lines cost £826.40 in goods, £55.20 in domestic freight, £52.90 in service fee, £147.20 in shipping across eight parcels and £25.00 in QC, which is £1,106.70 landed and £42.57 per line (Recorded, one batch).
Compare that £42.57 with the £42.53 of the middle pot and the scaling story ends. The batch doubled, the paperwork doubled, and the unit cost moved backwards by 4 pence, because parcel count grew at the same rate as line count.
Past this point the lever is not money but structure: fewer parcels per line, lighter packaging, and lines chosen for weight rather than for how they photograph.
Stop adding goods when the unit cost stops falling. The third batch moved the per-line figure by 4 pence against a doubling of the money committed, which is the clearest signal in this whole article that the next £600 belongs somewhere other than the goods column.
Spend the next increment on packaging and line selection instead. Lighter packaging moves a parcel down a rung of the ladder, and choosing lines for volume rather than for photographs is the same decision made one step earlier.
Pricing from the landed figure rather than the listing figure
Price from the landed figure. A line that lands at £12.40 needs £24.80 to double the money before any marketplace fee, and the fee then comes out of that £24.80 rather than out of the £8.20 listing figure the eye prefers.
1. Write the landed figure for each line. 2. Multiply by the multiple you need. 3. Subtract the platform fee and postage. 4. Check the result against what similar items actually change hands for.
Anything about tax, VAT registration or import duty on onward selling inside the UK is outside our records and stays Not verified here. A pricing model built on an assumed tax position is a model with an unknown term in it.
Write the landed figure on the item before it is listed. A figure that lives in a spreadsheet and a figure that lives on the label behave differently when a price is cut, and the label version is the one that stops an item leaving below cost.
Re-price after any merge or split. A batch shipped as eight parcels and the same batch shipped as five have two different landed figures, and a price set before the change is a price set on a cost that no longer exists.
Keep a floor as well as a target. A landed figure of £12.40 sets a floor of £12.40 before any fee, and writing that floor beside the target stops the slow sizes from being cleared at a figure that never covered their freight.
Work the multiple through one line end to end. A hoodie that lands at £12.40 at a 1.0 kg rung needs £24.80 to double the money before fees, and after a platform fee of roughly a tenth and a £3.20 postage label the break-even figure sits near £31.00, which is the number to compare with what similar items actually change hands for.
Moving up a pot without stranding cash in the warehouse
Cash leaves the account when the item is paid for and comes back when it is sold, and the gap between the two is the real constraint. The 30-day free storage window we record is the outer edge of a comfortable gap (Recorded, reviewed 2026-09-04).
Grow the pot by one category at a time. Two categories in the £600 batch already produced a sizing spread; four categories in a £1,200 batch would produce four spreads and one storage bill.
Keep one measurement running through every batch: landed cost per line. It fell from £45.03 to £42.53 and then to £42.57, and that flat section is the honest signal that the next £600 should go into packaging and line selection rather than into more goods.
Move up a pot only after a category has cleared twice. One clearance can be luck, two clearances in the same category is a pattern, and the pattern is what justifies the extra money rather than the unit-cost arithmetic on its own.
Leave the last increment unspent until the warehouse is empty. A pot that is fully committed to goods has no room for a restock, a replacement or a price that moves while the batch is in transit, and that room is worth more than the marginal line it would have bought.
A stalled batch has a cost that never appears in the unit figure. Fourteen unsold lines across two months occupy shelf space, and although the first 30 days are free in the window we record, a second month at an unverified daily rate turns a stationary batch into a bill (Recorded for the window, Not verified for the rate).
A stalled batch has a monthly price rather than a one-off one. Fourteen unsold lines occupying shelf space through a second month turn a stationary batch into a recurring cost, while the same fourteen lines sold inside the first 30 days cost nothing for storage at all in the window we record (Recorded, reviewed 2026-09-04).
The data point behind this note
Landed cost per line averaged £45.03 in the £250 batch, £42.53 in the £600 batch and £42.57 in the £1,200 batch, so doubling the largest pot moved the unit cost by 4 pence (Recorded, 44 lines across three batches).
Rates last checked 2026-10-02. Where a figure is community-reported we say so; where we could not verify it, we write Not verified instead of estimating.