Outer Limits 4x4 Board

On my TB42 it has a clutch booster on it.It has always had a slight paint bubble next to the master cylinder.I pushed the clutch down last Sunday,and it went straight to the floor.It seems that all the fluid has been pushed out and it now has air bubbles.I was unable to remove the metal pipe from the cylinder so i pulled out the plunger (from the cylinder) to find a small seal.
I think this could be the problem but i`m not sure.I have been told approx. $200 for a kit.

QUESTION: Is this a common problem to happen in this spot,also does anyone know where i can get the seal cheaper from?

Repco- NOPE
Supercheap- HUH? whats that.

sound like the seals gone who ever told ya $200 is ripping u a good one

ABS: sells the seal on its own for $15 bucks well that what i paid anyways wont be more then $20 and damn lot cheaper then $200
they will have the seal even if they order it

i dont think its too common really

i was quoted from Kloster Ford today $40 trade for a kit which basically is the piston.
My mav`s also got 380000 kms on it, so i cant imagine how many times it`s been pushed in and out.