Green Man Gaming offers Steam downloads of Cities: Skylines for Windows, Mac, and Linux for $7.49. (Sign in to see this price; CDKeys offers it for a few cents more.) That's tied with last month's mention as the best price we've seen. (It's also a current low by $3, although most stores charge $30.)
CDKeys offers Steam downloads of Rocket League for Windows and Mac for $8.69. That's a buck under our mention from April and the best price we've seen for this soccer-meets-driving game. (It's also the best deal now by $6.)
Note: New customers can provide an email address on the CDKeys Facebook page to get a unique coupon code that cuts an extra 5% off.