you were hanging out at the crossroads when suddenly satan pops up out of no where offering you a sweet deal

You won a fortune of a distant relative of yours who passed away recently?

GOG charged you $100 for a $5.99 game

You were taking a walk, then stumbled upon the tens of thousands of protesters occupying Russian streets. You engaged some folk in conversation, one thing led to another, and now your world view has taken a positive tint now that you've met so many good people, working so hard at improving the lives of your people :)

You've been afflicted with Lycanthropy.

Calling dibs on $9.99 being the correct answer... so if that's the winning answer, it can be gifted back to you :)

you got to see the Liliger

The Enigmatic T parachuted down from the sky and landed directly atop your head; he profusely apologised and then proceeded to seductively dance in your general direction.

You were walking the street today when suddenly you found a wallet in the ground with $100 in it and you couldnt find the owner of the wallet. So you felt that it wasnt fair to stay with the $100 you found and decided to use this money to make a generous thing with it ,and this generous thing is this giveaway for us to spend $100 in GOG!!

You didn't receive anything you didn't want anyway. :-)

you received insurance money for something really silly

Books are a partial remedy for that ;~p

you completed a marathon

You went to the Balshoi for the first time?