We own a tub grinder and I can tell you that no one will rent you one. You can look for a contract grinder to come to you and grind for you. Depending on the material you may get a reduced rate if it is a saleable end product. The operational costs are to high to rent one out for someone. To hire someone will run you around $450-$500 an hour and that does not include the support equipment, meaning loaders to push the material to, and away from the grinder.