Auto body repair & detailing: Rear fender rust, rust area, rear fender

Question
I have a mazda protege 02.The left rear fender has the paint bubbled up like you can lift it and remove it but I am afraid to remove it because I know there is rust under it and has to be repaired.Yesterday I went to collision center to ask an advise or estimate and they asked me 699 dollars.The rust area is 4 or 5 square inch.I am an aircraft mechanic and I am very surprised about this price.Do you think I can repair this problem? Thank you.

Answer
ILIR.......THE RUST IS ON YOUR LEFT QUARTER PANEL AND YOU COULD CUT THE RUST OUT AND RIVET A NEW SHEETMETAL PIECE IN AND THEN FINISH OFF THE AREA. THEN YOU HAVE TO REFINISH THE QUARTER PANEL.
THE PRICE QUOTED DOES NOT SEEM TO BE OUT OF LINE.

WHEN YOU CUT THE RUST OUT AND PATCH WITH ANOTHER PIECE THE BEST WAY IS TO WELD THE  PATCH IN AND THEN FINISH.

THE COST JUST TO DO THE PAINT WORK ON THE PANEL IS APPROX HALF OF YOUR QUOTE.