Have you considered looking for a used one..?? 10 years ago, I bought a good, barely used, fully hydraulic Shaver HD-8, for 1/3 the price of a new one on ebay. It was a 3 hour one way drive to get it, but saving $1600.00, it was worth the trip for me. Plumbed it up to my old Ford 2000, anddrove 350 posts, with the only issue. broke a return spring after about 75 posts. Called local dealers that handled parts,and it was going to be 7-10 days before they could get one in. Checked online, and found Kencove fence supply, and they sold direct replacement aftermarket springs, for about 2/3 the price at local dealers, w/free shipping, and had them in 3 days. Ordered 2 just in case, but the first one I put on lasted the rest of the posts I drove.
Kencove Farm Fence Supplies - Kencove
I would suggest which ever one you choose, to get a full hydraulic tilt model. Worth the extra money, to tilt with hydraulics, rather that hand screw adjustments.
Look for one's from private individuals on Craigslist FB Marketplace, ebay, etc.