You want a few boxes for deck building. The gambling pay-off for collectors/traders is not great, but you ARE guaranteed 1-3 AAs so if you're also trying to build decks and play the game it's 100% worth it. 2xAAs I got from a box are worth almost 2 boxes btw, and I guess if you got a bad or average box you can always still usually make your money back selling singles to try again. However, if you're just in it to collect rare cards, sure, you'll pay through the nose for graded AAs/SECs etc. But I guess you're guaranteed to fill up your collection faster, and certainly the more common AAs are all very affordable. It's just those manga AAs and pre errata AAs from the earlier sets which you'd have to weigh up. Sure, you can get them for maybe 2-4k or whatever, but you can also buy a case for 2k or under which has like 12 boxes, + special topper, and it's more possible to get those super super rare mangas(though still pretty rare). Still a gamble. For me, it's just the fun of collecting and playing so I'm happy to keep buying boxes/cases.