I have successfully obtained a card for less than 25% the original listed amount, Cards like the one I'm referring to typically sold for under $100 and he had it listed for $400. In a few months he relisted it for $200 and I made a BO of $100 that was accepted. But that was a case where it was a Sizemore 1/1 and the seller just had no idea what the market was, and just wanted to get some money back off his box. In cases where it's a big dealer that doesn't care if they sit on a card for a decade, it's much tougher getting them to move even 25%, let alone 75%. For a card #/50, you just have to let that one copy go.