I have like 5 pairs of "nice" sun glasses that I cycle through now, but mainly just 2 of them as I have prescription in those 2 pairs.  I keep 1 of the other pairs in my car as a backup in case I forget to grab a pair when I am going somewhere.  
My wife works in optical so I get huge discounts on my frames.  Even with that, the most expensive ones I have are the Maui Jim's that I have right now.  The frame was like $80 (with her discount, usually like $240) but with Maui Jim, if you want prescription, you HAVE to go through them so she doesn't get a discount on that, and it was $200 for the prescription lenses.  So $280 total is the most expensive I've spent on glasses, and again, that's with her discount.
My other prescription pair is a Tom Ford pair and I think total that was about $180 since she could get a discount on lenses for those because they can use their normal supplier for that.  
The other 3 pairs that are non-prescription she got for me from her previous job. 1 was a free Revo pair a distributor gave her, one is Barton Perreira that was $250 with her discount, and one is Oliver People's that was $200 with her discount.
Before when I only had cheap glasses I used to lose them within like 2-3 weeks.  Now though I've had pairs for years.