Leveling accounts isn't the best way to do it in my opinion...
I buy lvl 77 and up accounts.. Best price I've ever gotten was $70 for the account.. Anything less than $100 is worth it since Vanilla+BC+WOTLK costs $70 at the cheapest, then you've gotta spend 2 weeks leveling the toon from 1-80.. I'd rather spend $100 and make it back in that 2 weeks.
I too buy wow accounts, generally I only buy lvl 70 - 75 and I get them under $50.
I got lucky and bought a 70 hunter, with WOTLK enabled for $30 once
Also bought 2x lvl 70 BC accounts for $20 each.