Hello there. I understand that you may want to save money as a penny-pinched student, but if someone were to share such a file with you, unless there were some sort of arrangement through a library (i.e. borrowing an e-copy through such an institution), the sharing party would certainly be violating the copyrights held by GMAC®, and I would not advise anyone to pursue such a course of action.
Your best bet for free access to the digital form of the Official Guide questions is through GMAT Club. The forums there are full of top-notch discussions on official questions, which is to say those that come straight from the guide. In fact, I myself participate in the discussions on a regular basis. If you were to practice the questions before looking at the discussions below, then you could get plenty of quality studying in at little to no cost. Many of the questions even have little timers, and if you create an account on the site, all of your responses are saved in an error log automatically.
Good luck with your studies.