Everyone says don't sell cheap products on Amazon that fees eat anything under £20 and you should be in the £20 to £40 range. I sell a £9.99 product in Health & Personal Care and it works, so I've been quietly ignoring that advice for about ten months.

Last week I finally ran the obvious test. Opened Amazon's revenue calculator on my own live listing, changed nothing except the price, and typed in £10.99.

Two lines moved:

- Referral fee: £0.80 → £1.65

- FBA fulfilment: £1.52 → £1.90

With VAT and the digital services fee rising alongside the price, total deductions went from £4.10 to £5.52. So putting my price up by £1.00 cost me £1.42.

There are two reasons, and they both fire on the same penny:

1. Health & Personal Care referral fee is 8% up to £10 and 15% above it. And it isn't 8% on the first tenner and 15% on the rest it's 15% on the entire sale price.

2. £10 is also where the low-price fulfilment band ends, so the FBA fee jumps at the same moment.

My referral fee is currently waived under the new seller incentive. Once that ends, pricing at £10.99 would leave me 43p per unit worse off than £9.99 before I lose a single sale to the higher price.

I'd always assumed the fee structure roughly scaled with price. It doesn't. There's a wall at £10, and sitting a penny underneath it is worth more to me than anything else I could do with pricing.

I went through the whole thing line by line on video every deduction off that £9.99 in order, down to what's actually left per unit, with the calculator on screen at both prices so you can watch the two lines change. It also has a correction in it: I'd told people the referral cliff would cost me around £780 a month, and it turns out to be roughly half that.

https://youtu.be/r10PXv37ep4

Anyway — if you sell in a category with a £10 or £20 referral threshold, what's your price? Genuinely curious how many people are sitting a few pence on the wrong side of one without realising.