The cost basis is recorded for each item.  Keep track of the total cost basis like you do for the total value and total game count.  Keep this value private though like other cost basis info.

I have too many games in my collection to keep track of mentally. I'd like to instantly see which games in a lot I already have so I can calculate weather or not it's worth buying a lot to get bulk games I need.

The Epoch Cassette Vision is the first Japanese exclusive video game console to feature interchangeable game cartridges. Of thirteen known games, only eleven were released.

I'm trying to collect the entire PS3 catalog and having the option to only see games I do not have in my collection would greatly increase the efficiency of searching.

Please add prices for Japanese Mega Drive games!! There are a lot of exclusives that didn't even get an European release...

Also, thanks for already adding Famicom and Super Famicom!!

Adding The cartridges for the Texas Instruments TI-99/4A would be nifty .Mattels Hyperscan would be a shortlist  but might be nice as well. 

The Commodore Amiga CD32 is a CD based videogame console of the 90s. 

Please add support for it.

Thanks!

I have gotten to the point where I have amassed a good collection. I think it would be super cool for a weekend activity to have some sort of randomizer to choose a game from the collection to play. Also, to have a filter to filter out consoles or only include a select few. Not only to filter out consoles, but also features. Such as games that include multiplayer, or specific genre of game a person is in the mood to play. 

I found a duplicate game of the same system (PS4) one with a long title and another with a short title.

"Mark McMorris Infinite Air" and "Infinite Air"

I did not find an easy way to report it, that's why I make this suggestion. Maybe adding a clickable button of "Report duplicate" at the side or bottom of the page or something.

Thank you very much