FLOSS doesn't require that you give your software away for free. It's totally fine to require payment. (Now, the traditional 'sell copies of software' doesn't

FLOSS doesn't require that you give your software away for free. It's totally fine to require payment. (Now, the traditional 'sell copies of software' doesn't work so well for FLOSS, since every customer of yours can start selling it themselves, or give it away to anyone, which is why this approach is rare. But it's still FLOSS)