IF IT AIN'T BROKE.....
My advice, take it from many websites, piece together the bits you want and use examples from other sites for different ways of saying the same thing. Change its wording slightly and put the sentences back to front sometimes. If it's altered, not in the same format and slightly different it's ok.
Honestly, the questin is like asking "Is it okay to copy code from another project?" And the answer is the same: if it works the way you want it to work, and you won't get in trouble for using it, then go for it. The way to determine if it works the way you want it to work is to consult a lawyer.
Don't think of legalese as if it were just marketing BS; think of it as an odd programming language for the legal system. When you need Python code written or evaluated, you become or hire a Python programmer; when you need legalese written or evalauted, you become or hire a lawyer. It's as simple as that.
creative commons too
I agree on finding a legit free source.
How does selling it, whether it can be found that you copied it, or whether people read them affect that it's a copyright violation? It's a copyright violation if you publish it as your own, irrespective of whether people read it or find out that you plagiarized it.
Seriously, though, we wrote ours ourselves, but we did heavily use info we gleaned from other peoples' ToS. If you're just a generic web 2.0 site you can probably get away with using someone else's generic ToS, but if you're doing anything slightly different, you'll have to tailor it anyway.
FWIW, for microPledge we ended up with http://micropledge.com/conditions -- we got a lawyer friend to look over it briefly, and he gave us a few good pointers.