$500 for the part (I checked around) plus $100 in labor. I couldn't do it myself because there was so much going on just to get to it.
Around the same time I switched to power brakes on my '72 Nova 4 door. Roughly $350 in parts and I did the labor with a buddy in my driveway with a simple set of hand tools. I also bought a good 350 for a '78 van for $400 (missing carb/intake), so their are some advantages.
It's all up to start with car wise. At 40 many old cars have had so much replaced it's tough to accuse them of being "40 years old" anymore.
I'm not a parent, I can't speak to hauling kids around in one, but economically it makes more sense for me to drive something I can fix cheaply and myself (or with minimal help).