Chris,
I checked w/NAPA a few weeks ago for a NEW master cylinder for my 52. New, (not rebuilt) M/C was quoted at $169.99. Mine wasn't as bad as yours sounds, so I ended up buying the kit, and rebuilding it myself.
I believe the rebuild kit was around $22.00 w/tax and all.
Depending upon which model you have, I've seen them in some of the catalogs, i.e. Jim Carter's etc. for between $140 - $160. Alot of the parts places are offering special holiday savings right now, discounts and free shipping etc. so that might be a good place to check.
Also saw several on E-Bay, when I was looking that were advertised as being NOS. They were selling for around $80 on average, if I remember correctly.
