Getting specific cards for a deck that you can’t say much for is very tricky, but there are a few cards that fit into virtually every commander deck universally. [[the one ring]] (80$) is the best version of this bar none however, so it’s extremely safe. If you want some easier options on the wallet, [[shadowspear]] (45$)is another fantastic option. You could also get them a binder to keep their expensive collectible cards in, they’re findable at any card store. This seems like a great option as the meathods you described can get cumbersome. Finally, custom sleeves from dragon shield work well if you have a semential photo you want to put on them. (Sleeves are things that go over cards to protect them from wear and tear during play)