Interesting, but wouldn't you need a server somewhere to act as the other end of the tunnel, for which you'd have to pay for hosting and/or bandwidth anyway?
But hosting and bandwith for servers is extremely cheap if you don't care about reliability and trendyness. You can get a vps with 1Tb bandwidth/month for $4 (probably even less if you look around more than I did). Try getting mobile bandwidth for anything near that price.