I started selling cards 20 years ago when my son got into YuGioh. It started as a sideline but grew into a well known cards store Cardzandstuff4you. Some of my biggest sellers were cards bundles, as they are a great budget friendly way of starting in a game and adding to a collection for a fraction of the cost of new sealed packs. I found most people selling them only included very basic and unusable cards and rarely anything with a value of over £1.
I decided that wasn’t fair. I buy in collections of cards and then split them up and put them into my bundles. I don’t take any cards out so whatever I get is included. That way there’s more of a chance for you to get the useful and sought after cards you need.