About one month for $5 and working 24/7
Wow lol. Looks like I'm not going to start mining antime soon. Maybe when I can afford one I'll get an AntMiner and mine Bitcoin. Thanks for the information, though.
If you get a less shit GPU, you can make a reasonable amount from zcash, eth, pasc, and xmr.
Get used Nanos/RX470s if you have relatively cheap electricity. Get 1070s or don't mine if you have expensive electricity, and consider used 290(x)/280/7970/7950 or fury(x) if you have free electricity.
Visit online calcs like mycryptobuddy.com, whattomine.com, etc for approx earnings, but difficulty is generally increasing so use their figures as the most optimistic scenario