There should be a little number next to the current price of  a game in your collection that shows how much the game was when you added it to your collection so you can see exactly how much a specific game has gone up or down since you've had it.

Add an undo button if you accidentally hit remove all games while doing a lot calculator. 

Change currency displayed to CAD, USD, etc etc

The value and price tracking for the Game Boy SP is quite the mess for the AGS-101 models (from what I can tell). 

1. The graphite version is listed as a black variant so it isn't getting any data (and probably hard for collectors to find)
2. Pearl Blue and Pearl Pink have a hard time receiving new data so prices aren't up to date
3. Pearl Blue isn't receiving data for CIB condition.

This is just what I noticed but I'm sure there are more issues within the Game Boy SP variants/colors. If this is something I can work on to save you time let me know and I can try to correct it. I'm still getting used to the interface and what my abilities are in editing existing items. 

Thanks for this wonderful website! It is amazingly useful!

please add the standard and the white snow edition for pal 

some way of contacting you so missing games can be added

The website does not work if you visit https://pricecharting.com/

You'll also want to make sure http non-www goes to https://www as well.

I see Heritage Auction listings for some games.  Can you input this data automatically, or at a minimum, provide a way for us to report Heritage Auction results in the same way that we can with eBay listings?