2010 Toyota Prius Master Cylinder Faulty - Repair Question?

recently a number of warning lights illuminated on my dashboard including traction control, emergency brake, abs, and brake system (yellow). following this, i noticed that i had an open recall on my vehicle for the brake booster pump and took it in to have the recall serviced. after they returned the vehicle to me all of the lights were off for about 24 hours. now the lights are back on and switch between all on and all off every 25 miles or so of driving. i can feel a noticeable difference in the breaking when the lights are on, and regenerative braking does not function. seems like i have traditional brakes, but nothing more.

i eventually took the car back in to see what was up and they told me that my car's master cylinder is faulty and quoted me ~$2,500 to repair.

1. i was wondering if this repair quote is excessive by the toyota dealership? online research suggested that the cylinder is only around $500
2. i am wondering if it is worth getting done at all given i estimate my car to only be worth around $3,500 at best. (2010 model year, 155,000 miles, a couple points of small damage to body, tire pressure sensors don't work)

iam not really a car person at all and thank you all for any insight or information you would be able to provide to me on this situation. very much appreciated.