Yeah, at $300, used is probably the only way to go for us Clyde's. Bike shops will often have used bikes. it may be tedious, but if you decide to go the Craigslist route, post some of your finds here--the guys n gals would be glad to give you pointers.
Regarding BikesDirect or Bikeisland, i think this is a great way to go if you want to learn how to build/maintain your bike, or if you can have a buddy help you with assembly.