There’s a “Pay what you want” sale over at the Crayon Physics web site. It’s normally $20 bucks via steam or the website (paypal, non-steam). You can get it pay whatever you want for it via the paypal route until January 15. The game’s supposed to be really good, and what’ve you got to lose for a cent (if you want to be a dick about it)
https://www.crayonphysics.com/
https://en.wikipedia.org/wiki/Crayon_Physics