OK, so <sigh> where to start... I don't want to post a wall of text that you won't read, so I'm going to
try and keep this short.
I started detailing cars back in the '80's as a high school job. I kept at it as a side business detailing high end exotics until about 6 years ago when my spine made me give it up for good. So I have a bit of experience in this area.
In my opinion, XPEL film is top notch. Yes, there are other good brands, especially since the PPF market has exploded the last few years, but XPEL continues to be the target the other players are hoping to match.
I was introduced to XPEL's self-healing PPF at SEMA in either 2013 or 2014. I was so amazed at the demonstration... it was a true ground breaking product. And honestly, it still is.
Anyway...
Getting your entire car PFF'd is a great idea, IMO, but as you've found out, it is also extremely expensive. If you don't mind paying the rather handsome price, and the PPF'er you're considering has a great reputation, go ahead and have them do it. You'll find that this is one of those "you get what you pay for" type deals. Don't try to value shop PPF installation! You're either going to end up with a cheap brand of film, a bad installation job, or both. Research the place(s) that you're considering, and get referrals. Don't go by user reviews off of Yelp and the like... call some of their customers and ask them personally.
And there's also an alternative to professional installation: Do it yourself.
While installing PPF isn't by any means hard, it isn't altogether easy, either. BUT, many places will sell you pre-cut kits for your car. And it is so much cheaper to buy these kits, that you can often time mess up many of the pieces, and still be money ahead by re-purchasing the parts that you messed up.
There are a ton of YouTube videos out there that will teach you the basics of PPF installation.
If you do decide to go this route, try to get a pre-cut kit. It is exponentially more difficult to apply PPF that isn't already specifically cut out for the panel that you're applying it to.
At a bare minimum, PPF the front bumper, the first 1/4 of the hood, the area just in front of the rear tires, the side view mirrors, and the rocker panels. Many places will allow you to specify the thicker, more impact tolerant films for these harsh environment areas, which I recommend.
FWIW.