Anyone work at Goodwill?

How the f... do they decide their prices?

I was just in there today looking around and came across this little bottle of acrylic paint. The .50 one you buy at Wal-Mart, Apple barrel I think is the brand. Literally .50 at Wal-Mart. But why buy a new bottle at Wal-Mart for .50 when you can buy a used bottle at goodwill for .99?