Very Few vendors at a show will/would have Repop signs For Sale unless that was their business. GO to shows, make friends, pickup signs an Really look at them. When in Doubt ASK others that are standing around looking at stuff. EDUCATE Yourself, Don't rely on Pay Pal/Ebay to get your money back 'cause you made Mistake[s].
On ebay, before bidding look at other auctions held by seller, check their past auctions, check their Feedback, check their Location/Country. Ask Yourself WHY a seller in INDIA/ Argentina would have soo many American signs?
Ask Yourself WHY any seller would have Multiples of any sign? It does happen but Not to often anymore for someone to have found a Bulk Plant they cleaned out.