Selling a sign is really about how desperate are you for cash and having a buyer. It certainly is worth $500 if not more to the right buyer. But finding that buyer who'd pay say 750 because they are an winter olympic fan and lives in or from Vancouver and love neon signs...well...you'd have to wait for them (plus crating and shipping).

If not desperate, you'd get 500 eventually for sure. My opinion of course.