http://www.fiverr.com/ is also an option
You get what you pay for, but it might be worth five bucks to give it a shot. My biggest concern with a strategy like this is you might be seen as a spammer even though you're not the one directly doing the spamming.
Maybe I'm just cynical, but anyone who supposedly has 10,000 followers on twitter and is willing to say ANYTHING to them for $5 may not have the best followers.