I purchase bulk ammunition online frequently, and have always had excellent results. Generally speaking it is less expensive than most of the ammunition in town, and while it is often bulk military hardball rather than hunting loads, it is fine for range training.
My only caution is that should anyone (say, for example, some activist group or a hacker or Rupert Murdoch's journalists or whatever) decide to take a look at what you're ordering online, the general public would no doubt freak out about anyone ordering ammunition in 500 or 1000 or 5000 round bulk lots.
So, there is that to consider...
Treat everyone you meet with dignity and respect....but have a plan to kill them just in case.