I think that the best way fot this, a steady income over time, is buying in the all time low, and then wait for a long time or you can do some trading with cryptos.
this is a good strategy - buying when the price is super low and selling when it reaches to your goal price amount. Trading crypto is very exciting especially when you notice some pump and dump - your quick move shall be to position yourself for profit in either pump or dump situation.
But how can you say that it is an steady income? As you will not sell them until you don't see a higher price and sometimes it may even take months for price to go higher.