Yep, they are spendy from Forster.
My eyes are always open at gunshows for Bonanza benchrest die sets, since they are old, they usually sell cheap, like $20. If I really can't wait to find one (BR seater die) at a gunshow, one can be found for about 1/2 price of a new Forster on ebay. I have swapped out almost all of the Seater dies from my Lee rifle die sets...I even mod'd a 7mm STW Bonanza BR seater for my 6.5x257R.