I have a couple of very small VPS's which cost $15-20 per year. That's less than the cost of a cup of coffee per month. There are plenty of similar offers on sites like LowEndBox.com. A few SSH tunnels on a minimal Debian install shouldn't take up more than 64MB of RAM, so you don't really need an expensive Linode for that.

Caveat: These low-cost "companies" go out of business all the time, so you'd better read the reviews. But since I consider them disposable anyway, I don't really care if the uptime isn't 99.9% or the company goes bankrupt after 9 months. If you plan to do anything other than tunneling with your VPS, I'd suggest that you pay at least $10 per month.

You can get a year on Amazon for free.