Croissant is free to use from start to finish. There are no hidden charges, no cost to get buybacks, and no cost to use the extension — and shipping is free when you send us items to sell.
The one time a fee applies
If an item you send in doesn't meet our quality standards and you choose to have it shipped back to you, you'll cover that return shipping. That's the only fee. See What are Croissant's quality standards? and What happens when an item isn't accepted.
Is there a paid plan?
Croissant itself is free. There's also an optional membership — Croissant Premium — that gives you more credit back when you shop, plus monthly credit. It's entirely optional; you never need it to use Croissant. See What is Croissant Premium?.