Get a pen and paper!
Ok figure out your rate!
How much fuel per hour does the rig burn?
How much will the operator make ( multiply x 1.6 = effective wage rate)
How much PM time per 8hr work shift ( ie grease, fuel, blade sharpening)
How much mobilization is to be included or do you have to show up ready to work regardless of how long it takes you to get there?
What is the Amortization period and how many hours per year to you expect to devide the yearly value by to set your equipments hard dollar cost at?
How much profit do you expect ? Ie 25-30 %
Now that you have determined that figure the same info based on a brand new piece of equipment your number will be significantly higher! The number with the new iron is the price you should charge! Your negotiation can occurr in the arbitrage between the new and the used price!
Check your number by calling a local rental store or contractor that rents his side arm mower out plus wages, mobilization, and profit
This should give you a better number to start with!
So in short I am telling you to do a bit more home work $90/hr is pretty cheep for a $175/hr piece of equipment!
Thanks
Jon