F0XT Servers pay their bills through user's purchases. There are a lot of costs involved with running dedicated game servers, automated backups, databases and websites. these costs increase linearly with the amount of players, with some amount of constant overhead.
That being said, whether or not something is worth your money varies for each person. If you would rather be playing a different game that just came out, then enjoying the perks of a server rank, that's totally ok. but some people will prefer enjoying additional perks on a game they already love, over doing something new they probably won't as much.
I do not know if/when we are releasing a store for pixelmon though, I suppose it depends on what Kain and Emtron want.