The repair shop has got to mark up parts prices, that is how they make money! You can buy a used master cyl. for that price, 40. to 45. but not a new high quility one, i,ve checked! Also labor rates are high, i agree, but the mechanic's dont work for nothing either, in fact not enough! The shop has other expenses too like: the FACILITY, garage liability insurance, 'high dollar' tool's and equipment, utility cost, shop supplies, HASMAT disposal etc. A top quality, complete mast. cyl. for that vehicle is going to cost around 130.00 (plus). You can skimp on some parts but not brakes! The shop is doing you a favor by having a real mechanic install top drawer 'BRAKE' parts since nothing will take their place when you need to STOP!!!
Do you if its part is New,Re-manufactured/Rebuilt? Sometimes its hard to believe but one gets what one pays for... So i recommend you compare Warranty (Parts/Labor),Brand because a Master Cylinder play a very important roll within the brake system of any vehicle. Good luck.