Flat fee or commission

There are two ways to get paid for a film. A flat fee pays you for the work. Commission pays you for the result. The difference is not the money, it is who carries the risk.

Who carries the risk

With a flat fee the brand has bought something before they know whether it works. With commission they have moved that risk onto you: if the film flops you worked for free.

That does not make commission a bad arrangement. It makes it an arrangement where you should be paid for the risk you took over.

Work out break-even before you answer

Ask what you would have charged as a flat fee. Divide it by the commission per unit sold. The number you get is how many sales are needed for the commission to be equivalent.

If that number is higher than what you seriously believe you can sell, the offer is a pay cut in disguise.

The third option

A lower flat fee plus commission. You get something regardless, they pay less up front, and both of you gain if the film does well. It is more often the right answer than either extreme, and almost nobody proposes it for you.

A first job with an unknown brand

Do not take pure commission there. You know nothing about how well their site converts, how often they run out of stock or how they handle returns, and all of it decides your pay without you being able to affect it.