you can begin by using ultra short-term funds, where money can be put in or taken out at any time, as required. Choosing such a fund is not too difficult either since the returns for most of these is similar. This is because a large amount of corporate money is invested in such funds, making it important for fund houses to run the product competitively.
It is important to shortlist 3-4 funds to invest in as and when money is available.
Yes, you can invest in a bank, as long as it is publicly traded. However, don't base your stock investments based on knowledge of GTAV. The real world stock market is different and it is much harder to "double" your money, especially if you are not investing that much to begin with. Remember investing with stocks is a long term commitment, very few people actually make short term gains and most people who are trying to get short term gains actually lose money.
Is it possible to invest in my bank regardless the little money that i have. Will it work?. I wanted to double my money like they do in GTA 5. Invest in stock market then they give you cash after investment.