A steal will make you lose around 0,2% of your gold, an attack around 1% (the exact figures depend on a few factors, as how much gold is out,...).
Hitting someone will reward you with the same gold amount regardless how much gold your opponent has out (depending on builds, he might be dtw when no gold is out). Gold rewarded will depend on respective strength and therefore someone with def pots will award you a better payout.