I think that half of my gear has a silver or black X on it from an REI garage sale!
My town has the smallest REI store in the country, and it's walking distance from my apartment!
They have a garage sale about every 2 months and I often try to go to them. I seldom *need* anything, but I go for the entertainment value and often pick up something.
The store is small and the crowd isn't so huge that they let everyone in at 10am and it's a bit of a feeding frenzy. It's usually outside in the parking lot.
The list of great stuff I've gotten for cheap cheap cheap is long. A few things come to mind: a NOS in box 13" Novara Randonee frame for $15 (it's my commuter bike now), two REI Taj tents for $30 & $40 (it's our favorite tent, we got one for spare parts, they don't make them anymore, $200 new), I got slightly used Pearl Izumi Quest mtn bike shoes for $11. My friend got a new K2 Twister road bike, built with whatever was around, including Ultegra 9sp shifters for $200. I have REI camelbak type packs for $5. I just got some PI winter booties for $3. We got REI zipoff pants with broken fly zippers for $2, a friend fixed the zippers for us. I got a North Face Apex jacket for $20.
We have gotten some things so cheap that I sell them on ebay for a profit.
Specialized Ruby
Gunnar Sport
Salsa Vaya Ti
Novara Randonee x2
Motobecane Fantom CXX (Surly Crosscheck)
Jamis Dragon