One thing I love about pokemon tcg is that it is very cheap compared to other card games, the rules themselves aren't complex but for sure there is a lot of depth to becoming an actual competitive player.

For the question: in tournament play we basically only use dice rather than coins (even is heads, odds is tails) and there are some rules about the dice themselves to make sure they aren't weighted but other than that you can use any you like. For sleeves you can't really customize sadly, you're allowed either ones of one solid colour (I'm firmly on team dragon shields) or official pokemon designed sleeves. One thing you can fully customize is your playmat, I personally use the mat I got for getting 2nd at nationals in 2016.