300 MH/s is quite low.

I am building now a Mining-Farm with 150 Rigs each 230 MH/s with 6 GPUs due the fact to buy such an amount of hardware each rig cost me 3400 Euro.
Powercost are 0.08 Euro.
But only with solomining ... i will get round about 31,5 GH/s from them.
Daily Powercosts are ~ 230 Euro,
rentment for datacenter round about 10 Euro,
human resources ~ 100 Euro,
profit ~ 1340 Euro.
So that 1000 Euro daily will let me reach my ROI something between 470 - 520 days, depending on the exchange-rates.

But with 300 MH/s and such high powercosts it will be hard to reach roi