I used to spend around 20-50 USD a month, but I stopped collecting. However, I'm back and collecting again, but I doubt I'll be spending as much as I used to.
not too much, I guess around $15 to $45. I also play Magic, but that's a different story.
I only play Pokémon for the fun but I don't collect cards. So I may have rares that people want and I trade them away for things I need for my decks. I'm not really competitive these days as I was before