To get the answer, you need to weigh your tractor trailer empty. When you get that weight, Lets talk numbers, this is wrong but it is a big example. If your tractor trailer is 35,000 pounds empty....
By the time you factor in everything, such as truck payment, fuel, insurances, tags, paying yourself ,and a myriad of other things, it runs between $1.35 and $1.50 per mile.
Cargo insurance varies greatly depending on what type of cargo you insure and the coverage limit. You can see rates ranging from around $1,000 per year to several thousand.