Not unless it is involved in the interstate transport of commercial products.
In most states vehicles registered and licensed for "farm use" are restricted in their usage, usually in the distance they may travel in relation to where the farm is located.
Yes
That will vary from state to state.
The FHWA inspection is required annually, and it's not limited to just Class 8 trucks.
A DOT annual is required at least once a year.
You need to have the number displayed, and documentation of the validity of the DOT number.
As much as the facility providing the service charges. That's how the price is determined - not by state.
should only need a dot number if it is used for a commercial purpose
Any commercial vehicle of more than 10,000 lbs. GVW requires an FHWA annual inspection sticker before going on a public roadway. The exception being towed driveaway vehicles enroute to a dealership - the dealership will perform the DOT annual.
As much as they charge. It's not set by the state, it's set by the company performing the service.
Dot 3
DOT stands for Department of Transportation.
Laws on this vary by jurisdiction. You need to contact the DOT/DMV of your state to determine this.