CD Keys has the Forza Horizon 3 and Hot Wheels bundle for 40.19 right now. Base game is still normally $50 and the DLC is normally $20. Decent deal if you don't want to wait for them to go on sale individually or need both.
Alternatively the Hot Wheels DLC is 13.39
Base game isn't on "sale" right now but is 37.49
Also, Blizzard Mountain is on sale from MS at the moment for 9.99