Topic: Value of boxed NES games

I have 7 boxed (different conditions) NES games, and wanted to know their value. The games are:
•Rad Racer
•Super Mario Bros
•Adventure Island Classic
•Darkwing Duck
•Teenage Mutant Hero Turtles
•Kung Fu*
•The Simpsons, BART vs. the Space Mutants

I find the best way to do this is go on eBay and check the listings for each item. Rather than look at what people are currently selling them for, you can look at Completed listings to see what they actually sold for and when.

Also helpful:
http://videogames.pricecharting.com

Super Mario Bros. is probably worth something when boxed (since most people who originally got the game got it without a box), likely Darkwing Duck and I don't know how rare Adventure Island Classic is, but it gives away that your games are probably PAL (as AIC was a later release than the US version). Since I heard NES didn't sell nearly as well in PAL regions, that would probably affect the scarcity but I don't know how much.

Collectors can be really picky. The condition and production year can have a significant effect on the value. The best way to discern value is to check ebay listings and compare them to sell prices, not listing prices, the price they actually sold at.