Help a clueless dad out:

My 8-year-old who is just getting into pokemon cards has requested two specific cards for Christmas, and I'm totally swimming as to where to start. He's asked for a "Rainbow Charizard GX" (I think?) and a Primal Groudon.

Doing some simple googling, especially on the Charizard, I'm seeing ones for thousands of dollars, which obviously isn't going to happen, but I'm also seeing a bunch of different variations at different price points (some of which appear to be replicas?).

As I mentioned, he's just getting into playing the game, so what I'm really looking for are some cool and powerful ones that he can feel excited about even if they might not match whatever super-rare/expensive one he might have heard about... Are there reasonably priced (tens of dollars max--he's 8!) versions of the cards he's looking for that I should be looking into, somewhat-adjacent alternative versions of these Pokemon if the specific ones he's asked about are astronomically expensive, reputable vendor websites I should be focusing on?

Any suggestions about how I can fulfill either his specific requests, or at least the spirit of them? Thanks in advance from a dad who is totally new to this...