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.
I believe you missed the boat when it comes to purchasing bitcoin to become a millionaire as well as mining bitcoin. However there are many other alt coins out there which could possibly take bitcoins top spot one day. Do some research into some of the alt coins and try and see which ones may be worth investing into at these low prices.
I prefer forex and binary trading than bitcoin mining, you get small profit but you spend more on equipment and electricity, and there are many scams on bitcoin than trading.