Do any of you know of a place that has a very good guide for retro game prices, including the condition and of course rarity of the game? I've seen quite a few but some are wayyy off.

Ebay completed listings and averaging them is the best way. I only look at auction prices as buy it nows tend to be very overpriced, yet people do buy them. If you get really into collecting, then you will become your own best tool. I remember a couple of years ago I became a walking price book. I could tell you the price based on condition, time of year, etc... You will pick it up naturally trust me. Like I said though, best bet is to take advantage of ebays completed listing function.

dinky dana from youtube has a store locator and a price guide just goto his website http://www.dinkydana.com