"translating" what Chris says: if you really love it, and want it for your enjoyment, and pay 300 USD for it, you most probably haven't been duped. (Although it's always worth trying to negotiate a lower price, of course.) On the other hand, if you plan to resell it for 300 USD within the next 50 years, you're unlikely to succeed. (After that, you just may, one never knows the antique market that far in advance.)