This post has basically been answered, but I wanted to add a couple of things...
1. Xanax, like most (but not all) benzos, are not water soluble, so snorting it would be wasteful. Taking xanax orally is really the only way to use it effectvely. You can dissolve the pill under your tongue to speed up the asorption, if you don't want to wit a whole hour for oral onset.
2. Also, like other benzos, xanax is difficult to overdose on, BUT ONLY IF IT'S NOT MIXED wth anything (capital letters for emphasis on safety here.) Benzos are quite safe on their own, which is one of he reasons they replaced barbiturates as the premiere class of annxiolytics and soporifics. Once xanax is combined with other substances though, particularly alcohol and other depressants, the chance of death or risky behavior (blackouts, taking more drugs and forgetting one did so...leading to taking even more drugs, etc.) increases drastically, so obviously combining xanax with other substances is not recommended.
3. You should start out with 0.5 mg. Since you dont have a tolerance, that should suit you fine. And you can always dose up, but you can't dose down.