I hope I'm not too late here.

I used to play online poker years ago. This particulate story takes place about 12 years ago. I won't name the site but this was a site that later down the road was caught up in a massive scandal

I used to play a lot of heads up Sit-N-Go's on there.

One day I only had $11 left and decided to play a $10 Heads up match and unfortunately lost, when a game ends it asks you if you want a rematch, the opponent agreed to one and so did I although I didn't have enough funds left in the account to pay for another match. There was no error just a blank screen so I closed out and went back to my account page and realized that I had been given the $10 back although I just lost it.

So I figured I'd try this again and worked out that there was loophole where if you didn't have enough money in your account for a rematch and agreed to one anyways you'd always get the buy in amount back.

So I then got my then GF to setup an account and then we setup a third account. We'd both deposit $20, play a $20 heads up match and then we'd agreed to a rematch. This meant the winner had $40 and the loser gained $20 out of nowhere. We then transferred the winnings into a third account and kept repeating this for free money.

We managed to gain a fair bit of free money doing this and I ended up being able to play high stakes poker online for fun. My average account balance was around $30k and whenever I was short, I'd play a $5k heads up match to get a free $5k

In the end I managed to withdraw $7k out of the site and ended up with the actual money which was nice but when I got greedy and tried cashing out $25k they caught on.

I ended up getting banned from the site for life after they found out that I managed to manipulate a bug and also that I got free money out of there.

TL;DR - Found a bug in online poker software and ended up profiting $7k