MichaelMeissner:
I'm not sure it makes economic sense to buy kits like the RBBB these days, unless you have special needs, as the integrated devices are now in the same range.Lets see, the Sparkfun Pro Mini (328p based) is $10 (currently out of stock, but presumably they will restock shortly). There are a lot of clones of the Pro Mini running around, depending on how you feel about using a cloned product.
Pololu just announced a $13 32U4 based microprocessor, A-Star: Pololu - A-Star 32U4 Micro
Adafruit recently mentioned that they will be coming out with a Pro Trinket, that I think they said would be 328p based.
The Digispark Pro is currently in kickstarter, and when it hits retail, it will be in that range.
I get my Arduino Pro Mini clones on eBay, $20 for 5. They ship out of New York. I just made a socket for them in my designs, so if a user burns up something in it, I can just mail them a new one.