1616 Patton Ave, Asheville, NC 28806
This is the best thrift store by far - it is the largest. It is clean, has clean bathrooms, changing rooms, drinking fountains, plenty of parking, safe location, etc. Tons of high quality merchandise. Mostly great prices, with a few things marked higher than normal by the staff (though not nearly as overdone as other goodwills like the south asheville one).
If you're up for some real treasure hunting, also visit the Clearance Center, around the back of this store. It's tons of bins to dig through - purchases are $1.10/lb.