The best hardware (antminer K5) can get you 5 dollars a day per machine but it's expensive (1500-2000 dollars depending on your provider). Innosilicon A10 can get you 80% of that profit (like 4 dollars a day) for under 500 dollars every machine (pay for themselves in 3-4 months). There are some for under 50 dollars but they get you like half a dollar a day (If your eletricity is cheap) so they're not worth it unless you buy a lot of them.
In any case if you want to live off that you'll need at least 10 machines.
In any case if you want to live off that you'll need at least 10 machines.