I have never used Crossover and haven't read about it in years so my info could be out of date. Last I heard it's free as long as you compile it yourself - which I can't help you with because I am CURSED when it comes to compiling software. I just can't do it no matter how hard I try.
If you pay for it, it's much easier to install (presumably you get a precompiled binary) and you get voting rights to decide which games they should support.
Oh and yeah, from what I've read, it does support more than WINE, at least in theory. It's actually built on WINE so theoretically anything that works on Crossover should also work with pure WINE, although presumably it will be a lot more difficult.