Another good way to earn money in single player mode is speculation. If you don't know how to make money on the stock market in GTA 5, you should read this article and find the answers to all your questions. Of course, it involves some risk, however, there is a little trick. The fact is that at some point you progress through the main storyline, Lester will offer Franklin missions to eliminate unwanted people, then the open will indicate what the company's going bankrupt, and which, conversely, will enjoy a fabulous growth. Correctly using this information we can in a short time and without much effort to earn a very decent amount and know what stocks to buy in GTA 5.
Act according to the following plan: after the cutscene where Lester tells Franklin about what the company is about to become a market leader, we need to die to make the time to cancel the mission, then to run to escape to bet all your money on a specified firm. Better to do it immediately all the characters and put all the money there. Don't be afraid, you will not lose. Immediately after the mission, the shares of the company will jump by 20%, and after 2 games of the day will rise again, up to 85%. It is best to pass these missions after the end of the game when you already have millions. The income that you will receive if you pass the mission immediately, will certainly pleasant, but it is nothing compared to what you can earn, if you show patience.
Also information about the imminent bankruptcy or unexpected growth of any company can slip in conversations with the characters side missions, listen carefully to their conversations, so don't miss your luck.
Of course, you can play the stock market without these "tips", but the income will be less and risk more. In the end, you play as criminals, ready for any dirty tricks to earn extra hundred thousand bloody dollars.