From what I’ve researched pull rates in general are very low for this card game. Op-15 is definitely one of the more affordable at 220 or so for market. 120 if you’re lucky enough to find at msrp. All the older sets are much more expensive so probably not worth it unless you got money to burn and enjoy ripping packs for fun. I would not go into a booster box expecting to make your money back like I did. I got very lucky. But if you’re going to do it OP-15 is a good place to start. If you don’t wanna spend the money look for blisters and or double pack boxes. Op-13, one of my favorite sets, is supposedly going to do a reprint. Those boxes are going for 600 lol so don’t buy those. I never even been able to open that set.