I have been operating a GPU ETH mining rig since the December 2017, the total cost so far to build it has been $1,661. That's a lot of money for just ~ 58MH/s hashing power. Now, things were different back in December 2017, let's see how does it works out now (August/September 2018).
Building a 12 GPU Ethereum Mining Rig From Scratch - Part 1: Ordering Details
For most of the Summer my Ethereum mining rig has been powered of (because of unprofitable mining - high electricity price / low etheruem price)
Mining ethereum August 2018
I turned on my mining rig for 24 hours, and mined 0.00417899 ETH (with ETH changing hand at $276.18) that gives me about $1.15. Not bad, but let's see how much we are spending here:
Ethereum mining calculator with 0.2$ per KWh
It turns out, I'm actually losing 0.4 dollars per day right now. Sure, I'm paying a hefty price 0.2$ per KWh and I could move my mining rig to some cheaper location, like for example Georgia, paying just 0.1$ per KWh and in theory I would generate a small profit even now:
Ethereum Mining Calculator with 0.1$ per KWh
Cheapest Electricity in Europe for crypto mining (Cost per kWh) 2018
Since December 2017, I have mined in total 0.54398387 ETH. To break even my base investment $1,661 ETH should reach $3.060 (hard, but doable).
Last time I measured, the price for ETH was well above $5,000 (now, this is a great achievement already)
To Break Even My GPU Mining Rig, Ethereum Should Reach $5,153