use comicsvalue.com as a price guide
Since 2013, we are providing an archive of past comics auctions. Most of the comics have been auctioned at ebay, certainly the largest auction house for rare comic books.
Online auction houses are a very popular method for buying or selling comics. At comicsvalue.com, you can check the final auction price that a certain comic has brought. Although this might not be a true indication of the comic's real value, it does show what collectors are paying for rare items.
There is no fixed price for a second-hand comic, no matter how rare it is. The price of a rare comic is purely determined by what people are prepared to pay for it.
Never sell or buy comics without first checking prices on comicsvalue.com.