Everest windows priced

I had a quote for new windows for a 4 bed house, and 2 doors.

Everest came round to quote, and made the usual sales pitch. At the time of visiting they quoted £17,999!

Long story short, after some back and forth, they’ve come back with a price of £7,999.

I have no intention of going with them out of principle, and merely indulged them to see just how much they were trying to rip me off (my goal was £10k off, hence the post).

Has anyone else had similar experience?