I purchased this county line auger with a 12 inch auger bit. Works so well. Out the door 750.00 dollars for both the auger, and bit. The item does not come with any gear oil for the auger. Be sure to pick some up while you are there. I believe 80w-90. It will save you a trip should you decide to go with it.
https://www.tractorsupply.com/tsc/product/countyline-post-hole-digger
https://www.tractorsupply.com/tsc/product/countyline-post-hole-digger