Does this repair cost seem reasonable?

My 2001 Dodge Dakota 4.7 4x4 developed a power steering leak that became serious enough to need repair.
I took it to my local trusted auto repair shop and they diagnosed it saying the high pressure and return hoses need to be replaced as well as the cooler unit needs to be replaced. And the system flushed and filled.
I crawled under the truck and looked around myself thinking that I might replace these parts myself. I found that all of these metal to metal connectors are highly rusted and the chances would be great that I might damage these connections making them incredibly difficult to remove. Plus trying to do this repair laying on my back on the floor of my garage under a jacked up truck would seem to be a little difficult.
The shop told me it was going to cost me $780.00 to do this work which seemed quite steep to me. When I was considering doing the work myself, I contacted a parts store and found that I can buy both hoses for under $75.00. I didn't get a price on the cooler, but I wouldn't think it would cost much.
I'm wondering if this seems reasonable for this work, or am I being ripped off.
Thanks,
harkauto

The cooler is easy to replace. Lines little difficult. I would think 2 hours flat rate on repairs plus parts. 100-150 hour times 2 plus parts plus fluid.does sound high. Get one or 2 more quotes. There are some aftermarket repair lines splices if it was only one piece leaking.cooler cost around 25 dollars at local parts store near me.