Amazing test prep, well worth the money

I started studying for the GRE about 1 month before I took the test. I had bought the official GRE test prep book, but ended up searching for another test prep resource. I found out about magoosh, tried the trial, and gladly paid for the premium version. You have the ability to make your own customizable quizzes from their database of questions (difficulty level, number of questions, question topic); each question also has a full written and video explanation of the answer. I ended up using magoosh as my only prep source, and got a very good GRE score on my first try.