Valve cover gaskets and grommets should only be about $20.

EDIT: These days its probably closer to $30 or $40 but what exactly are you getting? If its $120, maybe it comes with more stuff than you need.

EDIT AGAIN: Its very odd that a shop is encouraging (or even allowing) you to bring your own parts. Thats something that they make a call to the parts store and have it delivered in 30 minutes, everywhere has them. Ive worked for both sides of this. Something seems off which is why I suggest getting another quote. Too many shady mechanics these days.

Also many times, if you bring your own parts, the shop wont guarantee anything. You could drive away, still have the leak, and they can say, "its your parts, youll have to pay labor for us to fix it again". Ive seen it a few times.

 

I agree - $450 in labor alone is nuts for that job. Sounds like they rattled off a bunch of tasks to make it sound complicated. But stuff like 'remove upper mounts' is literally taking off 2 very easily accessible nuts and rotating the dog bones - its every bit of 60 seconds worth of work if you include the round trip to the toolbox and back for the socket + ratchet, lol. I also agree $120 in parts is off too unless you're buying a complete gasket replacement kit or something.

Whtmonte makes a good point about bringing your own parts too. IMO if youre having a shop do it, have them do the whole thing including sourcing materials. Keeps you out of the liability of 'your cheap parts broke / didn't fit, you owe us extra labor money'.