Hmm… I’ve mainly used boxes from products like bundles and the Commander Legends/Kaldheim Commander deck boxes. Those I’ll use vertically rather than on the side. Ive also seen people recommend the plastic Ultra Pro deck boxes like this Ultra Pro 80 Card Deck Box - Black https://www.amazon.com/dp/B0002TT3B6/ref=cm_sw_r_cp_api_glt_fabc_WKHM91SQZTSNZJB3G3T7?_encoding=UTF8&psc=1 because they’re on the cheaper end, so if they get distressed, it’s not much of a loss.
I would also think plastic might be better than any sort of textile due to moisture.
One neat thing i find with the standard UltraPro deck boxes is that they hold one (sleeved) expansion per box, so you can sort them quite nicely. They also come in a bunch of colours. You'd need a separate case to actually hold the deck boxes though.
I didn't know about these. I use these often times: https://www.amazon.com/Ultra-Pro-Card-Deck-Box/dp/B0002TT3B6 They're opaque so that can be a pain, but they're cheap, sturdy, and relatively small. You can also write on the edge of them in pen to mark what's in each box.
You can get 2 individual Ultra Pro deck 60 card holders, they are like $5 each.
They come in a lot of colors if you want to try and match it with your pokemon type/sleeves.
There are specific boxes for storing your decks in, and the starter deck might even come with a cardboard box that is designed for that (but it’s usually cheap). No need to go all out on accessories, but if you want you can find pretty cheap Ultra Pro deck boxes in a variety of colors. Here is an example of the generic Ultra Pro box: Ultra Pro 80 Card Deck Box - Black https://www.amazon.com/dp/B0002TT3B6/ref=cm_sw_r_cp_api_i_fJTZDbYJVJ7Q8
Another thing I might recommend is card sleeves. These protect your cards in your deck from getting damaged, and generally makes shuffling easier. They can be slippery at first, but once you play with them more they work well. They also come in a variety of colors, which makes it a fun way to personalize your decks! Only use 1 color per deck to avoid obvious cheating though haha: Ultra Pro UPR85604 Eclipse Standard Matte Card Sleeves https://www.amazon.com/dp/B07B8CJHTH/ref=cm_sw_r_cp_api_i_bOTZDb50A39NK
Amazon lists the dimensions as 2.8 x 6.4 x 1.8 inches
Here is a small deck box, which is what I think of when I hear the term.
There's also the shoebox (or bigger) for storing lots of cards. Easy to add tabs to organize large collections of cards.
Take some measures to be sure, But I'm thinking one of these bad boys would help https://www.amazon.com/dp/B0002TT3B6/ref=cm_sw_r_apan_glt_fabc_AMM0P4RAXPATYGM9J3B8?_encoding=UTF8&psc=1
I wouldn't say "terrible value card game purchases." I'd rather say that card games, in general, are a rather costly hobby to have. For physical card games, you pay for sleeves to protect your cards, deck boxes, the cards themselves, and a playmat (and also maybe even a tube to roll up and carry the playmat in, which sounds silly but it's actually quite helpful). If you have multiple decks, these prices add up quite a bit (though you only really need 1 playmat unless you want a new one for a different art).
Card games, in general, are an expensive hobby. However compare this to this. Both get the job done; they carry your deck. There are, of course, other deck boxes in the price range between these two that have different aesthetics and carry dice and other objects, and you also have to remember about build quality as well when it comes to price.
It's all about the individual and their personal sense of value. One guy may be completely content with a $5 ultra pro box and ultra pro sleeves and a $10 mat, whereas another person may want to be more flashy. These aesthetics tell others about who you are as a player.
Now, I know that there is a huge difference between digital and physical card games in terms of the value of the cards themselves and that you want "better sleeves to better protect your investment" and whatnot, but that is a completely different discussion altogether.
this may help https://www.amazon.com/Ultra-Pro-Card-Deck-Box/dp/B0002TT3B6
its probably not what you are looking for, but its a start. playing cards can fit into this as well. ive seen these things at Walmart as well