House edge is the only avenue where the gambling industries are using to make their own money, though this charges varies from websites to websites and the percentage also differs however 0% house edge gambling site should not be trusted because they will eventually scam you.
House edge is merely a probabilistic figure. It is NOT site commission. 0% house edge means both u & house has equal winning probability in the long run. But, as bankroll of the house is in general bigger than an individual player, they manage to keep the bank rolling in the long run and hence make profit.