If I had the cash I would rent a server at Cyberbunker but it's to expensive to only run a relay there.
If you want to run your exit node anonymously, checkout chmuranet
They are in the seedbox business but accept tor exits, too.
You need to handle abuse within 24h. You need to use a reduced exit policy, but the important ports like 80 and 443 are fine.
It's a small company, so you have to ask if they can handle another tor exit. I'm currently their first and only exit.
You don't have to give them your name and they accept paypal and bitcoin.
Join their irc and ping wBuddha.