MOT + Maintenance bill

I have received the bill yesterday and I was not exactly happy. Partly my own fault as I brought the car only for APK without further mentioning. I was hoping the car would be good given it's history, perhaps a minor thing(s) only. The repair is something I could have done myself and as such could have saved a bit of money. I was only told the rear brakes needed repair so thought it was not a big deal. Turned out the whole breaking mechanism was seized and required replacement. Clearly the replacement parts (calipers) were not cheap, so that's something that could not have been avoided. The brake pads were very expensive. In any case, this has eaten up more money as anticipated leaving not much budget to tackle the other items I had on my list ...