The totally unofficial and use at your own risk....
These prices are from my personal experiences and dealings over the last 20 years. Prices can vary from area to area, and from situation to situation. Condition and originality are always King. This guide is not a iron clad rule please use it as a guide or tool only. With any collectable prices can and will go up and down as the market dictates. If you are collecting arcade games for an investment please reconsider this strategy. Asking prices on Ebay tend to be higher than average, as well as prices from commercial resellers. The prices listed are for working and complete games. Games lacking original components, with heavy damage, or non-working command less. Games which have little abuse, home use only, or owned by someone in the industry (former video game employees, etc.) can command a higher price. Always consult an expert before buying something you are not sure of.