Hesston Twine knife replacement blades

I'm needing some replacement twine blades for my 4550 baler and the online "good" deals have been $18-$20 and I guess that's per blade. I would like to buy maybe a dozen to be able to change them out ever so often. I can't find a A&I or Tisco listing for them. It looks as though the big square balers take the same blade 700718710. I just figure there's got to be a replacement blade at a cheaper price out there somewhere anyone have the same issues or have found the blades at a better price? bjr

Hesston Twine knife replacement blades