I used to play Pokemon TCG back in 2012-2015 competitively, then quit to pursue other adventures. As I spent my time, buying singles, participating in tournaments, and trading efficiently got my collection and cardpool up there in terms of deck building. As I started playing this TCG, I bought a booster box, and four Villains sets because I play and collect the TCG with my friend. We have a decent collection, two promo SS3 promo Gokus, two Jirens, playset of Senzu, within a two week period. We also entered a draft (both of us) and got more promos.

Depends how you approach the game and how competitive and invested you want to be. Cards can be pricey, all comes with the money you have.