I have to tick 661 titles that state they have box &/OR manual ???  Can I change the default to have box and manual ON please ?

just simply 

removal of duplicates

OR an option to just list the game once . . . and have an amount column ?

It would be very useful to buy or sell digital goods from your marketplace

Allow to bulk edit things in the collection, having to check things for every game gets tiresome with a big collection.

Also allow to easily change a game version from NTSC to PAL or JAP, since when I imported my collection it was added as NTSC even tough most of them are PAL.

golden sun PAL for gba is missing

The mission of pricecharting.com is to estimate "market price" for video games, which typically means what price a game sells for.

Reading the crawled non-auction listings for eBay, the site seems to be showing the "Buy it Now" price. But, eBay has a feature for buyers to put in offers on these "Buy it Now" only listings, and if the seller accepts one of these offers, the game typically sells lower than the "Buy it Now" price. And eBay doesn't appear to make the actual sales data public on these type of purchases. This means estimates on pricecharting.com could get a little inflated, depending on how much influence these "Buy it Now" eBay listings have.

You can publicly tell if a listing is accepting offers via the "Make Offer" button on the site. I think it would be useful to know that information from the crawl, and either use it to influence the estimate or simply annotate it on the web site.

Though, maybe you are already doing this in your estimation, and in that case, it could be noted in your methodology. :)

The graph displaying the values of my entire collection is nice, but I would like to see a graph of a certain system. For example, when selecting my NES collection, I would like to see the graph only display the values of my NES collection.