I'm tempted to go back through the pages here and tally up my rewards since the last 500K or 1M win because I'm currently on a crazy cold streak. As far as I can recall, my only "decent" wins over the past couple months were a 2 cars that I flipped for around 300K (or less) each.
6 star (Extra Menu 20: Shelby) -> Cr. 500k
6 star (Extra Menu 26: Maserati) -> Cr. 1 Mil
5 star (Extra Menu 52: Hyundai N) -> Lexus RC F GT3 prototype ‘16 (Emil Frey Racing)
I got curious to see if my impression that I've been on a crazy cold streak was accurate so I went back and tallied my DM rewards since Aug 1 and wow...yeah. In 2 months of opening daily marathon tickets I've won exactly 2 miilion credits total. That includes money gained by flipping the 4 cars I won. There were no 1M tickets, and only 2 500K tickets in that time. WILD! I've always considered 1.5M per month to be sort of the bare minimum you could count on...