Just go there. Check it out. No matter who you are, they have something in stock that you can use. It's like having multiple department, sporting goods, office, and home improvement stores in one giant warehouse. Also imagine it as everything on Craig's List all in one place and without the hassle of dealing with unreliable people and schedules. The prices typically beat CL prices so you don't need to haggle, but if you do think something is priced improperly, they'll discuss it.
Top that off with friendly service and pretty good hours.