(Disclosure: This site contains product affiliate links. We may receive a commission if you make a purchase after clicking on one of these links. Read our affiliate disclosure for more info.)
IndieGameStand has a pay what you want deal up for Cubetractor.
Min price is $0.25 for the DRM free version. Pay $1 or more for a Steam key. Beat the average price (currently $2) and you also get Dustforce (DRM Free + Steam key).