GTA Online can be extremely daunting for new players, or players returning to the game. The game has changed significantly since launch, and lots of new players might find it confusing as to what Missions would yield the best results in terms of Cash and RP.
The best way to make GTA$ and RP in GTA Online is, to buy up businesses that net you cash hourly, and carry out high paying Heists.
However, buying up businesses and apartments for Heists is still a ways away during the start, and players can often find themselves confused.
Here is a list of few missions in GTA Online that aren't necessarily that difficult, and pay quite decently. Some of these are unlocked after a certain level.
Furthermore, these missions can be completed alone. You don't always need to have your friends along or wait for Matchmaking with other players.
3 Best Solo missions for Money in GTA Online
1) Diamonds are for Trevor
This Contact Mission from Trevor isn't particularly hard to do, and pays out decently enough. Diamonds are for Trevor, as the name suggests, involves stealing Diamonds and delivering them to Trevor.
The mission pays out GTA$15540 in 8 minutes.
2) Out of Court Settlement
This mission is given to the player by Martin Madrazo and is unlocked at Level 22 in GTA Online. It is relatively simple, and involves killing one target and stealing the required documents.
The mission is relatively easy and can be finished quite quickly. It pays $9660 in 5 minutes.
3) Blow Up II
In addition to being a fun mission, it is also quite easy to do. It is made available to the player after achieving Level 20.
Simeon Yetarian gives this player to the GTA Online protagonist, and you must destroy a rival's car and 'repossess' a yellow Banshee in order to complete the mission. It pays $9600 in 5 minutes.