It's not always that bad (though often); it depends on the shop. Rummage sales are better: the people organising them tend to not filter out books or records as

It's not always that bad (though often); it depends on the shop. Rummage sales are better: the people organising them tend to not filter out books or records as a rule (church rummage sales in particular are good), because those things were donated explicitly for the purpose of selling them for some benefit, and reselling second hand stuff isn't their core business anyway.