Ya it would take awhile. But you have to start somewhere.
I was amazed at how many Genesis games are only worth $0.01...mostly loose sports games but still. It's also crazy how some games on Ebay have such varying prices. Like, if you do a search on completed listings for say...Mario 3. Loose it seems it ranges from about $0.99 to $10.00 or more!! A lot of it depends on when the auction ends. I've noticed with a game like that, popular, if it ends in the day on the weekend it gets significantly more.
You have to bear in mind that postage is included in the price. No one pays $0.01 for anything on ebay.
While it would be nice, I think it would be too much work for the time being. Games are still being added to the database. I'd like to have a thread like the "Submit missing games here" thread but for prices. Then we could debate the price amongst each other and get an accurate figure to agree on.
I also think European games should be in either Pounds or Euros, and American games should be in Dollars. One thing I don't like about the Digital Press guide is that everything is in Dollars. That means some European games are listed as $5 when they're actually worth around £5. It gets a bit confusing.