Sega GT/JSRF for PAL Xbox has been added now:

https://www.pricecharting.com/game/pal-xbox/sega-gt-2002-jsrf-combo

I've fixed the Tony Hawk 2 cover art issue.

Def Jam is here:  https://www.pricecharting.com/game/pal-xbox/def-jam-fight-for-ny

Some users are allowed to add missing items.  Any user can email us with missing games and we will add them.

The prices are based on sales from PAL regions.  ebay.uk ebay.de ebay.fr etc

Please let me know which ones you think are priced incorrectly and I'll look into it.

We do not use a straight average or a straight median.  We use a more complex valuation tool that takes into account the average and the median and other factors too.  You can read more about the methodology here:

https://www.pricecharting.com/page/methodology

Thanks for this suggestion.  I'll make a note of that so we can support inputting prices in other currencies.  For now, all amounts should be submitted in USD.

This feature is live in production.

https://blog.pricecharting.com/2019/08/record-cost-basis-for-collection-items.html

Thanks for the kind words on the site..  Yes, we would like to have all the color options for Gameboy released in the USA.  Were green and pink and purple GBC released in the USA?

Please include urls to photos of those so I make sure I'm adding the right hardware.  Colors can be a bit tricky sometimes on hardware items.

You can view other user's collections if they share the link to their collection.  We don't share it by default though for privacy reasons.  

Barcode readers will already work on the website already.  You just click in the search box, and use the scanner to put that number into the search box (you can even customize some barcode readers to automatically submit the search after the scan).  The focus of your mouse says on the search box so you can scan one after another after another.

Good point.  I was quoting from NBA Jam video game, but I'll edit it to make it "You're" instead.  This will gone live in the next server update.