Steal Cash from The Stores
As a change of pace, you can also knock over a convenience store or steal a car to pick up extra bucks. Car Theft has a pretty great return, although you can only perform thefts infrequently. Robberies can be fun, but they’re dangerous and not particularly cash efficient.
You step into one of the many potential stores (which include gas stations and different convenience stores), point a gun at the clerk, grab the money, and flee before the cops arrive. Online, a couple of new twists are added to the process. If you yell at the cashier he hurries the process up and gives you the money faster. Also there is a glitch instead of escaping the cops you can just go the online store from the menu and then return back to the game. Which allows you to loose the wanted level without loosing your money. So you can keep repeating this with other stores.
Los Santos Customs Mod Shops will purchase non-tracked cars for handy prices. Driving a jacked car to a nearby Mod Shop will garner a little extra spending money. Note that cops online are always on the lookout for stolen cars. The rewards can be substantial, although you can only sell one car per in-game day (48 minutes). SUV’s sell for good prices, ranging between 3,5K and 7K (Baller is worth 9k). Lampadeti Felon’s sell for $9,000+. For more Information view best selling cars.The math appears to be that the modshop sell price is 10% of any vehicles actual purchase price (which is why no car can be sold for more than $9,500, upgrades notwithstanding).
It is also worth considering using your second character to sell cars. That
is because all banked money is shared between your characters, but any one of your characters can only own three properties. Therefore, invest in a cheap 10-car garage if you have the money. At the start of any gaming session, use your double character advantage to go off hunting for any $6-9k cars, filling your garage. Find a seventh car, sell it. Now switch to your main character, play as normal, then roughly every 50 minutes, you can switch back to the mule and casually sell the held cars. Of course the additional benefit (particularly at this point in time) is that switching between your characters does a ‘manual’ save to the Rockstar online servers.
Simeon also has a varying wish list of high-priced rides. But from experience unless you get a sports car his average payment is $5000. He will text you a list of cars he desires. If you happen upon one of these, take it to a mod shop, respray it, then drive it down to the docks.
Or you can find upgrade cars near one of the gangs and if you steal that car you can sell it for around $12,000 without upgared since it is upgraded to the max.