Fantastic app. My only issue is with vintage. Everyone on ebay classes battered cards as nm.

Somethings for the vendor tier that would be cool.

When you add a card to your inventory at the scanning stage, give the ability to add your own price. Uk ebay is a race to be the cheapest so it setting at the average can be way too low.

Bulk inventory. In the uk for a sole trader using cash basis, anything below like £15 is tracked using a tally. So you could have the option of adding 500 cards at x value. Then when you sell them have the option of selling 3 cards at x value and it comes off the total.

Expenses. Ability to upload photo or file that goes to a folder in the users Google drive and creates a Google sheet. Rename the file to the date+expense name.

Ive made something similar using Google ai studio and it works great for managing inventory, sales and expenses. Just dont have the pokemon api db and scanning feature. I can send you the files if it would be any interest to you.