180Gh/s miner with price 0.409 B = $248.4
let's calculate :

per Day   0.00672406 BTC   $4.09
per Week   0.04706841 BTC   $28.60
per Month   0.20466352 BTC   $124.35

1 unit miner with 180Gh/s can't ROI in 1 month and electric cost?? are you thinking about it??. and difficult always increase every hours, day and weeks. This is unusable.
at this price, we will just throw money down the drain.