No one is going to want to hear what I am about to say but one of the cheapest ways to do this would be to buy a piece of 3/4" sch 80 black pipe to be sacrificial placed over the rod, and rent a small to medium sized electric hammer usually the equivalent to a 25 lb pneumatic will do the job,cut the pipe shorter than the rod use the hammer to drive it part ways in the ground then cut off some of the pipe as needed until the rod is driven to the required depth or the pipe is no longer needed to help keep the rod from bending