1997 Jeep Cherokee Water Pump replacement

After reading thru your site, I'm pretty sure I blew my water pump on the Cherokee. All the symptoms whine, now a leak. Called my local mechanic and without a thought quoted me 5 to 6 hundred dollars.

I think that's outrageous! I quickly priced out the pump, a new thermostat, gaskets and serpentine belt and that tallies below 125. Is it that difficult to replace this that they are asking/charging such an exhorbitant fee? Or should I find a new mechanic?

Thanks!