As with most car repairs, it's hard to judge unless all the details are known. But from my experience, it doesn't sound like an UNreasonable charge. I'm assuming it's the rubber lines that lead to each wheel cylinder, then the cost of the parts alone is probably $50-80. Figure the mechanics markup 100%, you're looking at $100-$150 for just the parts. In an ideal situation, you can probably change those lines out in about 15 minutes, but I'm assuming it's probably on an older truck, being exposed to the elements on the road. It can very easily turn into a 3+ hour job, especially if the lines aren't accesible and other parts (abs sensors, dust shields, etc) need to come off first. If any of the nuts are really stuck and stripped, then it just became a much more difficult job. I've changed out the brake lines on all my cars, sometimes they come off easily, and other times I'm cursing the whole time and wishing I had taken them into the mechanic. I don't even have corrosion to worry about on the west coast. So before you tell your friend she was ripped off, she might have actually gotten her money's worth.