so what's the minimal amount to invest and get about 5$ per day ?!
Daily payouts are too hard to have from legit business. I am afraid you may get struck with any HYIP or any ponzi with the rush you are showing. First of all, do not expect 10% return even for monthly basis. A better buy bitcoins and keep it in cold storage and watch your money growing.
Optionally, you may start lending business with your $50 worth of bitcoin. But you need to educate yourself a lot for better stay with that business otherwise the scammers will rob you out.