I have a feature request, which might be also interesting for others.

So I am working on a little app where I can track the prices of my collection, and on how much the cards gained or lost in price.
I have to maintain a second csv file where I have inserted two more columns and maintain the date I purchased a card and the price I paid for that card. I then misuse another column to mark the cards that I have listed in my second csv file. So I can very easily see in my app track the prices.

Is there a possibility to add those two columns?

This is actually an interesting idea, if it could be incorporated easily enough. I'm not big into the "investing" aspect, but I do buy a lot of singles, and it's nice to be able to look back and see when I've made a good purchase in hindsight, or learn from a bad purchase.