A very good question! I actually was thinking about this the other day, so now that it has been brought up I will try to itemize it and see where we are at.
Tank, stand, sump, and miscellaneous stuff that came with the setup: 800
Reeflo return pump: 280
MP 40 : 175 on craigslist (technically I got this when I still had the 90 but it was for this new tank)
mag 18 for skimmer: 125 on eBay
second sump/refugium: 100 craigslist
Sand and rocks: 100 from craigslist (the guy threw in the tomini tang and a pair of picasso clown fish as well!) This was a huge deal, because it was probably like 100 lbs of rocks and two full buckets of sand, plus the fish.
300w heater: I think 35 on drs foster smith
plumbing supplies: 60
Salt (so far): 100 (2 boxes of reef crystals)
filter media: 75
Total equipment: 1850
I already owned all the other equipment not listed. I will probably get another chinese led
panel which should run 100.
Now as for livestock I really haven't gotten much until recently. The fish that I have added are: sailfin tang (25), 2 firefish(12 for both), diamond goby (15), cardinal(10), and one anthias(20). I had a blue tang that died which was 30.
Most of the coral came from my old setup, I just recently started buying new frags (will post pics soon). I also have a couple reefer friends that I trade coral with, so I have probably only spent 50-75 on new coral since this tank was setup.
Snails, crabs, etc was probably about 50.
So that brings the total to right around 2k.
I sold the 90 gallon setup for 400 so Im back down to 1600 net.