My car squeals in the back and the back left tire is completely a rusted copper color

I badly need brakes and rotors. My car squeals in the back and the back left tire is completely a rusted copper color. And when I stop I have no stoppage power and brake goes straight to floor and takes a little time to come to a complete stop. Pepboys wants $755 dollars for front and back brakes and 4 new rotors, ntb wants 654, prices include labor. A friend of a friend said just buy the parts and he will charge me $100 for labor and thats it. I priced the parts on advanced auto. Com and came to $255 for frnt, back brakes, and 4 rotors. Thats for ceramic brakes, regular brakes are cheaper, which route should I go. I heard that ceramic dont make that much of a difference, true or false? He said that since im not going to be buying factory parts not to be alarmed if I hear squealing after he installs the parts, I never heard of this since last time I got brakes they weren't honda they were whatever Goodyear's stocks and they put them on and didnt hear any noise. He works for ntb and is doing this on his day off in his garage. Any advice or anything I should be aware of. I dont have a credit card, I will buy a prepaid one just to have and come back and make a donation if u would be kind enough to answer my 2 questions. Thank you sir.
matt