Actually, ANYTHING over 10,000 pounds FOR HIRE and crossing State lines requires the following:
DOT #.
FMCSA Motor Carrier Authority (Unless Private or Not For Hire).
Log Book beyond a certain air miles (states vary).
Minimum Liability coverage of $750,000, which is part of the requirement for being granted MCA (Unless Private or Not For Hire).
Annual Inspection Certificate.
Medical Fitness Card.
If you travel Nationwide and Not For Hire, I STRONGLY recommend a getting a USDOT number with NO state suffix, this means you are able to cross state lines as a NOT FOR HIRE entity and not get into AS MANY sticky spots as you would with a state suffix.
You still CANNOT haul for financial or other gain, unless it is for your OWN usage or you are moving YOUR boughten product to home.
They will want some sort of proof of ownership and MAY contact the person you claim you bought it from, so have the info and the "story" straight beforehand.
Even NOT FOR HIRE and PRIVATE carriers must still carry a DOT number, Med Card and adhere to DOT safety standards, logbook regs and scale rules, as well as the state-by-state tax permit necessities.
Oh, yeah, $2-$3 a loaded mile, AND DOT COMPLIANT, all the time is defiitely a nice dream.
Mark.