I'm in Canada where the promotions aren't quite as aggressive, but I've collected in the ballpark of $10k over the past three years through these free bet sportsbook promotions as well as collecting daily bonuses from this new wave of "sweepstakes" online casinos.

To make the "free" money and not ruin your life, You must have the discipline to look at things from a purely numbers perspective. It has to be mechanical and not emotional. If some action is +EV, and bet sizing is correct relative to variance, then you should perform the action. Never chase losses with a -EV bet.

The terrible thing about gambling is that there is no limit to how much you can lose, and you can also lose way more money than you actually have. It's a dangerous game.