You can also invest $50 in cloud mining. And each mining hosting has a minimum amount of equipment that you should have, for example, 10 ASICs at least. Both options are very risky.
Why take that particular risk when the profit margin with that amount is going to be very thin (assuming a legit cloud miner) and small?
To me, it's just not worth making a few dollars net profit per month out of $50, as it won't cover any expenses.