Pumping cost for a 135 acre center pivot this year was about $28 for natural gas fuel.  Some one stated that to do the same with a diesel would be about $70 for fuel.

I do not have an exact price on a new N.G. motor but I think they are over $10,000.  Pivot would be maybe $75,000, pump in the hole about $25,000.  Not sure what it would cost to dig the well. 

Give the motor a 15-20 year live.  Pivot 35 years for me.  Well life maybe 75 years and the pump life 25-35 years if you are blessed. 

Now those are the rough cost.  You get to do the math. 

Not cheap, but it will take land and double or triple the yield compared to dry land in my area.