If you are an arcade collector or wish to start on that collection of yours, then one great place to go is to a SuperAuction, which are held at various locations all over the US throughout the year. If you are curious to know if one will be coming to your area anytime from now until June of this year, you can check out the SuperAuctions Amusement calendar page. There they detail upcoming events, listing times, places and even the kinds of games you can expect to find there. From arcade to redemption to pinball titles, it seems like they always have something worth grabbing at these auctions.In fact there is on happening next week where they are selling over 500 items in Tennessee, which is too far for me but should definently prove worthwhile to those who can make it.
(thanks ti Eric Wang for pointing this out)