Many buy bitcoins and altcoins, they wait when the price will rise and sell. What other ways do you know?
You can start the business of buying and selling of bitcoin on localbitcoins or any other peer to peer crypto platform that enables one to trade with others on their platform specifying your own rate instead of buying or selling at the rate given to you.
It is possible to make a lot of money buying and selling on this platforms once you are able to build a good amount of trust from the users of the platform, the good thing about it is that they will always keep coming back to you once your first deal was successful.