...$500. The install is $500, why? I went to home depot, lowes, menards and they all have a similar install fee of $500 to install the sliding patio door. Why is this so expensive? Also, have people had good experiences with built in blinds on a sliding patio door?

I don't like the sliding door idea.
They are not very energy efficient.
drafty in the winter time,
warm in the summer time.
as for the blinds, what happens if they need to be adjusted or cleaned for that matter???
Does that mean you need to buy a whole new door??? That would suck.....
As for the install price, I guess that sounds about right, especially if you don't have one now....

The 'quote' for labor is relative to the installation only in so far as the slider R /O is a fit for the replacement...apparently you have a standard R / O and no complications involved..otherwise, the cost goes up accordingly.
{..R /O means rough opening...} if your new one were bigger, or taller, or the old one has been structurally a compromise to the structure, the cost of installation of a new one would change according to how much work it takes to fix or adjust or accommodate the installation.
I dont know much about the blinds. Sorry.

You can try posting a request at www.ThemBid.com for this job and local businesses/other users would bid on your request. This way you get to pick the bidder with the best offer. See if you can get a cheaper installment fee...

Bought a french door with built in blinds for my father from Home depot. Removed his old SGD, hardest part was the stucco. finish the job in less than a day. the blinds work sweet. Six months later my father is still very happy.

Regarding the cost... 2 laborers @ $50/hr, 5 hours, sounds about right.