REI / Second Ascent. Seattle is one of the best cities in the world to buy high-quality secondhand outdoors equipment — good to know, because brand new equipment is often really expensive. REI has a twice-yearly Garage Sale clearance event, but also has a clearance section downstairs where you can often find boots, down sleeping bags, tents, etc. with easily repairable damage at a fraction of the cost. Second Ascent, located in Ballard, is another great secondhand outdoors store.