I hate keeping track of all my card finances with spreadsheets all over the place, so I made a website to track card finances (entering purchase and sale data), which does all the calculations for me. I decided to publish it in case anyone else needs a good solution for tracking card finances. It's free to use btw
Check it out: synergycards.app
Please message me with any feedback or suggestions, as I'll be constantly improving this.
Thanks!