Just as a historical thought : When goldrushes where still a real thing ( not much unlike any crypto these days ) the people making real money where the ones selling commodities to the miners. It rang true for the gold-diggers and will likely ring true now. I just did the maths ( well I used the official Ether calc ) and it seems that about $140 can be had a month with one card. Now keep it mind, as more and more people jump on this wagon ( not much unlike gold ) the network hash rate goes up. So instead of worrying about your investment ROI going down as time ticks, sell them spades ( well I know you cannot really sell GPU's profitably as a one man show with $700 to spare, but you can write about it, even for other people and make money that way ) Or open a website with tips and use that $700 to get some black hat page 1'er
I spend about 10 - 20 hours writing to get $140, sitting cosy and warm behind my pc, so effectively my hash rate is 900 ( compared to a GPU with a hash of 25.
To get the gpu equivalent you would need to buy 36 of them. Granted I cannot ever be a gpu and run 24/7, but just saying.
