To be honest with you, by the time you rent a power snake, lug it home, deal with the crap on your hands, take a chance of hurting yourself, hoping you don't bust a pipe, and wondering if you are using the snake correctly, then hauling it back to the rental yard, I would much rather pay less than $100 bucks and letting a professional take care of this problem. Another great thing about bringing in a professional is the fact that they know the exact spot where the snake should be accessed.
Don't get me wrong, I love doing it myself and trying to save a buck or two, but sometimes logic takes over and I go the cheap way and call out those professionals.