What you keep on every sale

Two things can come out of a sale before it reaches you: the fee for processing the card, and whatever the platform takes. They behave very differently, and only one of them is unavoidable.

The card processing fee

Every card payment on the internet carries one. It is charged by the payment processor, which here is Stripe, and it is normally a percentage of the sale plus a small fixed amount. The exact rate depends on your country and the type of card, and Stripe publishes it openly.

This one is unavoidable. Anybody selling anything online pays a version of it, and it is the price of being able to take a card from a stranger's phone.

Because of the fixed part, very small sales lose a larger share to it than larger ones. That is worth knowing if you are considering a very low price: a bundle at a sensible price keeps more of itself than three tiny ones.

The platform commission

This is the one that varies enormously, and it is the one worth paying attention to, because it is a percentage of everything you ever sell rather than a fixed monthly cost. A commission of ten percent on a good month is a much larger number than it sounds when you first agree to it.

The maths worth doing

Compare a fixed monthly cost against a percentage at the volume you expect to reach, not the volume you have today. A percentage looks generous when you are selling nothing and expensive the moment something works, which is exactly the wrong way round.

Work out how many sales a month cover the fixed cost. For a modestly priced ebook it is usually a handful, and everything past that is yours.

What about tax

Digital products have their own tax rules in a number of places, and they depend on where you are and where your buyers are. This is worth twenty minutes with an accountant once, early, rather than a guess. Stripe keeps records of everything you sell, which is what they will want to see.