Do the drug deal mission but only kill the boss and take the briefcase. Then jump off the cliff and die. You will revive in the nearest hospital but only lose 500 dollars and keep 3,000 and the mission will be available again. Do mission until money you want is there.
How to make $120
Shoot or attack the vending machines which gives soda,don't stay close because it will explode.when it does you get $120 & one bottle of soda.