Actually we encourage people who redistribute free software to charge as much as they wish or can. If this seems surprising to you, please read on.
The word “free†has two legitimate general meanings; it can refer either to freedom or to price. When we speak of “free softwareâ€, we're talking about freedom, not price. (Think of “free speechâ€, not “free beerâ€.) Specifically, it means that a user is free to run the program, change the program, and redistribute the program with or without changes.
Free programs are sometimes distributed gratis, and sometimes for a substantial price. Often the same program is available in both ways from different places. The program is free regardless of the price, because users have freedom in using it.
Non-free programs are usually sold for a high price, but sometimes a store will give you a copy at no charge. That doesn't make it free software, though. Price or no price, the program is non-free because users don't have freedom.
Since free software is not a matter of price, a low price isn't more free, or closer to free. So if you are redistributing copies of free software, you might as well charge a substantial fee and make some money. Redistributing free software is a good and legitimate activity; if you do it, you might as well make a profit from it.