There are a number of GTA 5 Online missions that you can play on a single player mode. The top 5 solo missions that you can enjoy making money are the following.
San Andreas Seoul
In this single player mission, it is required that you steal the tanker filled with gas to be taken to Murrieta Heights. You should be able to evade the police immediately by getting some distance and allow the tanker to go off the main roads where you can hide in a smaller alley or industrial area. Good thing about driving a tanker is that you don’t have to steer around traffic. You can even smash your way straight into it, as nobody can argue with a truck this mean. You will unlock this level at Rank 16.
Crystal Clear Out II
Before you embark on this single player game, make sure that you are prepared enough for this job. By doing this, you will be able to earn big cash and have some fun. This is important because you need to kill a couple of groups of rednecks. This will be done using a second site and do the same thing in there. This level will be unlocked at Rank 16.
High Priority Case
By achieving Rank 25, you will be able to unlock this level. At this point, you are required to steal a briefcase situated at a guarded rooftop. So, you better have a helicopter and some weapons to be successful with it. Of course, it is part of the job to steal the helicopter first from the Vespucci Heliport, which you have to fly towards the rooftop of Maze Bank. A sniper rifle should be helpful in order to take down the enemies on the roof where you would get the briefcase. Then, get on over to the warehouse in Murrieta Heights.
Crystal Clear Out III
If you have gone far enough to Rank 40, you are going to enjoy this mission. Good thing about this mission is that you can do it alone. So, you have to be careful blowing up 3 meth labs, as well as kill every last one of the Los Santos Vagos in order to win this round. Don’t forget to bring in some firepower with you and a bad off-road car to help you out. Well, this is not that hard, anyway, just use some cover and kill everyone that gets in your way.
Brace yourself at Rank 50 because you are going to unlock another challenging round alone. This may seem a bit more complicated than usual, but it would take you a number of attempts to deliver a briefcase to Madroza before getting it right. Just don’t use aerial vehicle yet when you enter Fort Zancudo because you will surely be pulverized along the way. Just travel by land and use the map to locate Fort Zancudo on the West side.
You will surely earn RP and money when doing missions in GTA 5 Online. However, you may choose low-level missions if you are a beginner before you take on the higher levels.