What is the minimum p/m you should run power only loads?

I'm getting out of car hauling and might be running power only loads for a while out of the north east till I decide what trailer i want to buy.
How much per mile do you charge to move a non loadout trailer?
I'll be taking loads off the boards at first, I know they pay less than direct customers.

 

My cost is low but that doesn't mean I should charge the lowest I can. I was just wondering what the average rate is today.

 

Yea I plan on getting a trailer but don't want to sit around till I decide on what I want. So I'll run power loads for a month or 6. I'm looking at truckersedge using the demo and some loads are for $1 a mile and some are for $3 and most aren't posting the rate.

 

My truck is a haul and tow currently which I am selling and putting the 5th wheel back. My current cost would be different than running power. My truck gets 10 mpg, so $5000 for fuel per 10,000 miles. Insurance, PM, loadboards, cell phone and all other subscription services cost me about $1350 a month. I put 10-20% of NET away for incidentals/repairs ect...
I average $2 per mile currently running 2/3 car. So out of 20k gross after all my expenses and max 20% put aside I net just about $11,000. All my equipment is paid off and my truck currently stands at 101k miles so no expensive repairs should be popping up especially running so light.
Just my rough math. I'd actually pay less than $5,000 a month in fuel with my discounts.
I have never ran a semi. I had a ram 3500 and a 3 car trailer before this. This is my first class 8 truck and I haven't had it very long so maybe I am missing something in my math but this is why ask, so I can maybe learn something.

 

I won't know what the profit margins could be if I can't find out what an average rate would be and I never hauled a semi trailer yet, my truck is currently a straight 40ft truck and running very lightweight, so I can't really know my exact cost to operate yet without trying. I can only give a rough guess at what my expenses would be hauling 80k lbs.