I've used Poly.market a few times and been pretty happy with it - they use a second layer network, so after depositing, trades are fairly cheap (you just pay a

I've used Poly.market a few times and been pretty happy with it - they use a second layer network, so after depositing, trades are fairly cheap (you just pay a market maker fee, no crypto miner fee as far as I can tell). Downside is that the outcome is provided by the poly.market creators, but your actual bets are non-custodial.