One way which you can earn quick money is by doing robberies, this includes robbing 24/7 Stores, liquor stores, ATM's, armoured trucks and various heists in the game's story Missions. Below is a list of some of the robberies you can attempt, in most cases if you make a fast getaway after the robbery you should be able to avoid the cops easily as they are slow to react.
Robbery 1 - Supermarket
This supermarket is in Senora Freeway, Mount Chiliad has two cash registers and you can expect a payout of $950.
Robbery 2 - Limited LTD Gasoline
This gas station in Niland Avenue, Sandy Shores has two cash registers and you can expect a payout of $500.
Robbery 3 - 24/7 Supermarket
This supermaket in Niland Avenue, Sandy Shores has two cash registers and you can expect a payout of $200.
Robbery 4 - 24/7 Supermarket
This supermarket in Senora Freeway, Grand Senora Desert has two cash registers and you can expect a payout of $600.
Robbery 5 - Scoops Liquor Barn
This liquor store on Route 68, Grand Senora Desert has one cash register and you can expect a payout of $350.
Robbery 6 - 24/7 Supermarket
This supermarket on Route 68, Harmony has two cash registers and you can expect a payout of $200.
Robbery 7 - 24/7 Supermarket
This supermarket on Barbareno Road, Chumash has two cash registers and you can expect a payout of $1,100.
Robbery 8 - 24/7 Supermarket
This supermarket on Ineseno Road, Banham Canyon has two cash registers and you can expect a payout of $700.
Robbery 9 - Robs Liquor
This liquor store in Ineseno Road, Banham Canyon has one cash resister and you can expect a payout of $100.
Robbery 10 - Limited LTD Gasoline
This gas station on Tongva Drive, Banham Canyon has two cash registers and you can expect a payout of $1200.
Robbery 11 - 24/7 Supermarket
This supermarket on Clinton Avenue, Downtown Vinewood has two cash registers and you can expect a payout of $600.
Robbery 12 - 24/7 Supermarket
This supermarket on Palomino Freeway, Tatavian Mountains has two cash registers and you can expect a payout of $1050.
Robbery 13 - Limited LTD Gasoline
This gas station on E Mirror Drive, Mirror Park has two cash registers and you can expect a payout of $880.
Robbery 14 - Rob’s Liquor
This liquor store on Prosperity Street, Morningwood has one cash register and you can expect a payout of $600.
Robbery 15 - Rob’s Liquor
This liquor store on San Andreas Avenue, Vespucci Canals has one cash register and you can expect a payout of $600.
Robbery 16 - Limited LTD Gasoline
This gas station on Lindsay Circus, Little Seoul has two cash registers and you can expect a payout of $800.
Robbery 17 - Rob’s Liquor
This liquor store on El Rancho Boulevard, Murrieta Heights has one cash register and you can expect a payout of $700.
Robbery 18 - 24/7 Supermarket
This supermarket on Elgin Ave, Strawberry has two cash registers and you can expect a payout of $300.
Robbery 19 - Limited LTD Gasoline
This gas station on Grove Street, Davis has two cash registers and you can expect a payout of $880.
Bonus Robbery - Liquor Ace (only in GTAonline)
This liquor store on Algonquin Boulevard, Sandy Shores cannot be robbed in single player.
ATM Robberies
Hang around ATMs and wait for people to withdraw cash before robbing them, this is a good way to get money fast.
Infinite Ammu-nation Robberies
Use the following trick to keep robbing Ammu-nation Stores, this works because the money in Ammu-nation cash registers respawns quickly.
1) Head to an Ammu-nation store.
2) Shoot the clerk from the doorway.
3) Empty the cash registers.
4) Exit the store and walk about three car lengths away.Then turn around and re-enter store to find that the money has re-spawned.
5) Grab the cash, exit and repeat.
Armored Truck Robberies
A blue dot on the map will indicate there is an armored car. The goal of robbing an armored truck is to get the metal briefcase which will have $5,000 inside. If the briefcase has not yet been placed into the back of the armored truck it is just a matter of shooting the two armed guards and making off with it. If the briefcase is already in the back of the armoured truck you will need to break open the back doors which can be done by shooting 15-20 shots at the middle of both doors with a high caliber automatic weapon or planting sticky bombs to the back of it. If you get killed attempting this robbery you lose $500 or so for medical costs.