you dont have expansion modules

It is a hassle, especially if you have many items, to know whether your listed prices are in line with others who might also be selling the same game(s). An example is Amazon's "Match lowest Price" option for sellers. It keeps prices in check while also helping to curb artificially inflating game values.

We need to be able to communicate directly through the website. The e-mail messaging system gets lost with the hundreds of other e-mails I recieve. Plus it'd be a lot easier to organize and go through the messages and whatnot

It would be useful to be able to view the marketplace through the mobile app. I would especially be interested in features similar to the eBay mobile app. Mainly ones, such as getting a notification on my phone when an item sells. This would allow me to potentially ship sold items more quickly.

Let me see only listings with actual photos of the item instead of stock photos.

Your pricing on some rare games makes no sense - for instance Bang-O NEW sealed copy is less than a loose price. Obviously this makes no sense and your system should recognize this. Don't use any price would be better - although I found examples offered on games on Amazon. This is a bad flaw, and really hurts the credability of your site.

Please add:

2007 Legend of Zelda Twilight Princess card set (set list here The Legend of Zelda: Twilight Princess (trading cards) | CardGuide Wiki | Fandom)

2016 Legend of Zelda (set list here The Legend of Zelda Trading Cards - Zelda Wiki)

Neither of these have a good database with pictures

There was a new Panini set announced with the new Ocarina of Time release coming up so I think more people will be interested in collecting these cards.

Currently I don’t see a way to share or export the cards needed to complete a particular set. It’s great to see it in the app but there doesn’t appear to be a simple way to share that list with others to try and get the missing items 

somewhere between '+ Collection' and '+ Wishlist' I would like to see a simple '+1' and '-1' button. I regularly wait to add all my bulk cards from a single set until after I believe I am done purchasing packs en mass. I also try to keep at least 2 loose copies of every card I can in the event someone wants to trade. Having a button to quickly add 1, add another, etc. and scroll down would save me a TREMENDOUS amount of time when doing this, as opposed to the current method which usually involves opening a new page and manually typing in the amount of cards I am adding, then navigating the cursor to go back and scroll back down or close the new window.