free bet taxed?

Used one of those free bet promos last weekend, hit a nice parlay for a decent chunk. Now I'm wondering how the tax thing works with these. Is it just the winnings you have to worry about, or do you count the full payout including the free bet amount? Stuff seems kind of gray if you're mixing in bonuses and promos, and I don't want to trip up during tax season just for trying to get a little extra edge.

Never had an issue with casino promos since those losses mostly even out, but sports betting with free bets feels trickier. Would love to hear how others handle this, especially if you've dealt with similar payouts recently.