You can occasionally find HD800s headphones used, but expect to pay ~$1200 for a complete boxed set in excellent condition. I waited several months for the pair I recently purchased.
I run mine with a Quicksilver tube headphone amp and Moon Audio Black Dragon cables - a setup which, by audiophile standards, doesn't break the bank. For my listening tastes (mostly female vocals), I rarely take the volume knob past 10 o'clock. (If $$ were less of an issue, I would have looked closely at the Pass Labs HPA-1).
The 800s cans sound wonderful, though I find the HD600 series to be slightly more comfortable. Still, it's a worthwhile trade-off.
As always, YMMV.
Good luck in your quest!