Grind missions. There are some missions that pay $5-10k and only take 5 minutes or so to complete. Get a lobby of 3-4 decent players and just do them over and over. After the mission when you get to the debrief menu, hit like then spam RT and it'll restart
the mission without having to go back to the vote screen.
wow.....ummm...let's see....fast way to make A LOT OF MONEY?!?! hmmm.... well you can go around jumping in free roam shooting every other online player and get like your 1 RP and maybe 20 to 30 bucks like every idiot that joins my game.....or go do some
missions.....I prefer Survival mode....get 4 players going and get to wave 10 for $20, 0000....even at wave 8 you get $18, 000....get in a CREW and get bonus money and RP points!
I wouldn't recommend farming the same mission over and over,it probably makes money fastest but it is seriously repetitive,and taking turns with a friend to win races is lame too...i only managed 6 violent ducts before i nodded off to sleep.
Just do any missions that come up,join races between them,maybe a few survivals,DON'T faff around in free mode all the time(that's where you lose so much on medical expenses,and your time)pick up crates that drop.Your money mounts up in no time