Rob, yes rob. Just get into robbery and keep adding to your tally of riches from the beginning of the game itself. Secondly, investing in the stock market would be a good way of earning some quick riches. You should never lose out on the various game heists. Try making the maximum out of the six in-game heists, plan everything carefully and you may earn a huge share with each heist. Indulge in some random missions once a while and they may prove to be a good way of earning more. And last but not the least, why be a good Samaritan in the world of crime. Just hook on to the various cheat codes and earn your way through the game. Keep watching this space for more updates on GTA 5.