How much is to much?

I have been in the market for a 8 1/4 rear end to take the place of my 7 1/4 and I found a decent set up but I was told that I need to swap over to the B-body 10 inch drum breaks. My question is do I have any cheaper options and if not would it be best to just buy the breaks new or check out swap meets and craigslist?

I didnt know if I should post this under the drivetrain and transmission forums or brakes so I will prob. do both.