jmilane, I am afraid the only suggestion I can give you is to use discount coupons during the registration to get the lowest price possible. You can find some at
http://www.dncoupons.com
I do not know of any company/individual that would just give those away. You can also try to search the web for deals. From time to time I see startup domain registrars offering very low prices on names, like $2-3 per name.
If you are serious about the upcoming site, the cost of the domains is not a big investment, so I would not be cheap on such a critical part if that was really important.
Best,