The big guys dont sell wholesale directly to individuals. It would be bad form. They would ask you to become an authorized retailer. What a pain for a few buckets of balls.
There are companies out there that sell "overruns".
These balls are printed with logos (for corporate outing and events) that unsold or are no longer needed, so they are sold at a discount. Try ebay or gollballs.com for these discounted NEW balls.
http://www.golfballs.com/0001085/Logo-Overrun-Golf-Balls-Golf.html
Some companies will sell you slightly used balls at a deep discount, and if you think that you need that many this might be the best path for you.
Some sites are:
http://usedballs.tripod.com
http://www.golfballzone.com
If you are a beginner this is one of the best ways to get a high end ball at a discount.
The last way is to buy what are called "X-OUTS" and/or practice balls. They are balls deemed to imperfect to be sold as NEW. Most times there is a slight misprint so they are repackaged and sold at a discount.
Again: http://www.golfballs.com/ is a good place to start for these types of balls.
Good luck!