You might want to look at
http://prgmr.com/xen/ It's run by a Hacker News member, lsc.
He has plans starting at $5/mo but you'll want to take notice of the of the monthly transfer limit. The $5/mo plan is 10GB transfer a month (which will come to 5GB in/5GB out if you're using it as a proxy) so you won't want to tunnel video or downloads through it. If you go for the $8/mo plan though you can get 40GB data transfer.
I've never had an account with him so I'm not sure if there's a way to check how much of your data allowance you've used for the month. Someone else might be able to chime in about a program you could run on the server to notify you when you've reached a transfer threshold.