[nerdponx]

If you force anyone to pay for it, it's no longer FOSS.

If you force anyone who owns a copy of the software to pay for the source code, it's no longer FOSS. You absolutely can charge for said software.

[pierotofy]

I think the point was not about whether you can or cannot charge for it, but on forcing somebody to pay for it (you can charge for FOSS, but nobody is obliged to pay you for it if they get a copy).