t's also available directly for sale from Bitmain, and will actually make you some money after the halving, but not enough to roi. If you're loking for ROI, try the S9.
I find this statement of not being able to ROI not entirely truthful. If your electricity is good, which I think you have already done the math on because you're interested in mining, then it should be .07 or around there. Yes the difficulty will rise from s9 and that is more efficient, the s7 should still be able to ROI depending on price and difficulty after the halving.
I'm assuming his electricity is 0.10$/Kwh. The majority of people mining these days see around 0.1$/kwh. 0.07 is already more cheap than half the people of the US pay for their electricity, and assuming he comes from America, then he could very well pay for more than 0.07. Price is highly debated, but the current pump brings the price to near 777 as of now, and difficulty should face a narrow drop before rising. Of course, each day that passes lowers the reward, so if op were to buy the s7ln, he'd better do it soon- it's a possibility they'll stop selling it soon. If that happens, most resellers are selling the s7ln at 500+, so he's screwed. Bitmain shipping also has to be calculated, and depending on where he lives, the rates are different. I'm just assuming he's an average guy with average electricity. He didn't state at all what his cost for electricity was, so I'd think 0.10 is fair.