It doesn't make you anonymous. Torrent protocol wasn't designed with anonymity in mind and there are a million ways you're going to leak your actual IP address.
Tor is a TCP only network.
While this doesn't give you the anonymity you wanted, it will hurt the network for other users.
Most providers have long-term plans for less - like $3/month for 2-3 years. That's still the cost of eating a few meals out. Some of them even have port forwarding. Why spend double the money for less features?