Really comes down to how much you have to invest and the risk you are willing to take. If you are investing into cryptocurrency, there will always be some level of risk involved as the level of volatility is extremely high. For this reason, cryptocurrency investments may reap huge rewards but may also plummet and cause major losses. Other options include investing in precious materials such as gold and silver to hold for a long time, due to their finite supply, which will eventually cause their price to increase. Alternatively, stocks and ETFs are a good method to earn a small amount of money when investing into stable options, however, stocks may be a little risky if you do not perform the appropriate research and for this reason many people choose to invest in ETFs where their funds are diversified and there is a lower risk of losing money.