[Case12]

This has probably been asked 100 times. I am usually in the autograph board. But I'm trying to build some card collections for fun....no slabbing, just old used cards. Cards are usually pretty cheap. Here's the rub - I want a card that is not a reprint, even if a kid used it in his bicycle spokes. Example: I want a Joe Morgan rookie card. Inexpensive card. And some eBay sellers are fair and state RP. But if the seller does not say, and it's not marked on the back of the card, are there other hints? "Looks old" doesn't mean much to me. I can put a reprint in my jeans pocket and run it through the washer and dryer and it looks old. Looking for sage advice please??