I might let you share my WoW account, but I don't think that you sharing a runescape account would really be sufficient :S,
WoW = 14$ a month, + buying the expansion and such.. If you want to rent my account. I'd be worried about you taking my stuff on my character, even though i'm still kind of a lowbie.
If you can give me a good price, I'll consider it.
It's currently on a recurring membership plan, and I can cancel it at any time, but that also means that I can get the account back if you try ANYTHING at all. =) I'll check back in the morning.