For those who are concerned about saving traffic, but do not want to suffer with settings and manuals, I advise you to pay attention to Toonel.net .
For this tiny utility to work, you only need Java support in your operating system.
The program works with data transmitted via 3G/GPRS/DSL/CDMA, which is very important with the current spread of mobile Internet. Since only Java support is needed to work, the program turned out to be multiplatform (it works both in cell phones and desktop machines).
The settings are minimal (you can do nothing at all), and by default the program is ready to work at the first start (specify its default settings as a proxy in the browser — and go ahead). Without going into the subtleties of technology, I will say that the utility passes through itself and compresses data from HTTP, FTP, via SSL, POP, SMTP and IMAP, and can also compress graphics, which significantly reduces the traffic consumed. The program is portable (creates only one ini file), I use it daily from a USB flash drive (it is in autorun when mounting a USB flash drive, and its parameters are registered as a proxy in the browser), which allows you to save up to 50% of traffic sometimes without hesitation (as can be seen from the screenshot).