In my experience (and I have some wholesale accounts- you can try ingram, techdata, d&h, etc) the prices are always much higher than what I can find online-retail including shipping. Thus, my wholesale accounts are largely unused. I can't remember the last time I've purchased something through them.
If you do go the wholesale route, you'll find that most wholesalers require an application to be filled out which takes a few days to process sometimes. Even then, you aren't going to get a great deal on just 20-30 cdroms and no other purchases. I'd make an educated guess that at best your price will be a few bucks higher than newegg or googlegear. [for equivalent products-you might find some older equipment at a clearance price somewhere--such as the evertek link above].
Good luck though!