Savers seems to be the best. They actually pay for their items which is why I think they get Coach. If Goodwill gets Coach, they usually pull those out to sell it on ebay. But a lot of times Savers will overprice Coach. I got one for $5 in Las Vegas once. I think it was cheap only because it reeked of smoke. I also found two vintage wallets for $1 each.
Savers buys items? I donate to them often and they never buy items but they give me coupons for the donation. Like a 20% off coupon and a $3 off a minimum $10 dollar purchase.
They do overprice some bags but every Monday is 25% off day and Tuesday is 25% off for Seniors 55 and older. They also run 50% off specials periodically.
Another nice thing about Savers is that you can exchange the bag within a week if you have the receipt and the tags are still attached.