The deals for pre-packaged meds at ProficientRx are not better than AndaMeds, but what they offer is a free software package that is really sweet. It handles inventory to a "T" and prints peel-off labels on a regular printer. It is a useful turnkey. You can also enter and transact on inventory you buy from other sources such as AndaMeds, although I suspect that the difference is not often worth messing with the source of meds.
It's just easier not to have to deal with labels and software the way others have shown.