Generally speaking the metal cans are older and usually more valuable than the cardboard composite cans. However if you're just looking for atmosphere and don't want to spend a fortune on cans you can still find the common cardboard ones fairly cheap ($1.00 to 5.00). As a rule, the more interesting the graphics (pictures of cars, boats, airplanes, etc.) the more expensive the can, both cardboard and metal.

I have focused my cheap can collection on any cans with racing flags or called "racing oil" and branded service station cans (like Shell, Chevron RPM, Flying A, etc.).

If you want to get serious about cans guys like Scott Shipers can help you out, but be prepared to make an investment if you want the really good ones.

C Cragg