If you are talking about the GMC M135/211 series with the 4speed hydramatic, check Steelsoldiers.com They have a forum called the early deuce that covers this truck. Generally speaking $1500 for one that runs, less for a wreck, and if pristine, who knows... The Canadian army had lots of these, not so much in the US army. The M35 series won the long term contract.
Many contend the M135 was a better vehicle and way ahead of it's time.