Do I need new brakes?

[Mercedes Guy]

Today I noticed that when I brake hard I hear sort of a grinding noise coming from the front right wheel. I've never heard this noise before today. I also notice that my brakes squeak a little bit. They never used to do that either. It's a 1992 190E that I bought used about two years ago, so I don't know how many miles are on these brakes. Do these symptoms sound like I need new brakes? Since this is my first Mercedes I have no idea what new brakes should cost. Are they going to be expensive? I haven't been looking forward to the day it has to be worked on since it will probably be expensive. Any information would be greatly appreciated. Thanks.