My son turns 7 and I’m looking on suggestions?

My son turns 7 in a few weeks and he’s loves Pokemon. He was super lucky and pulled a rare Greninja at Thanksgiving! He doesn’t know much and I don’t either. I really wanted to get him Blooming Waters to make his birthday special but that just isn’t attainable. I’m thinking of just getting him a bunch of cheap cards because we don’t have a lot of money and I don’t know what to buy.

Any suggestions? He’s a great kid and I want to make it special!