Assuming we're talking about core backpacking gear, my experience has put me at just under the $1,000 mark for what I think is a fairly decent set-up.
I don't think any of my gear would be considered ultralight or top end stuff, but it is all quality gear ranging from entry to mid level.
When I say core gear, I'm thinking about the stuff from
this list that falls under either "The Essentials" or "Camping Gear" section; in otherwords it omits things under either the "Clothing" or "Extra Items" sections as well as some other things not on that list at all.
Pricing what I have based on that list, the following is the approximate break down:
- compass $50
- headlamp $20
- first-aid kit $20
- water bottle $10
- firestarter $10
- knife $40
- gear repair items $15
- whistle $5
- 70L backpack $110
- 2 man tent $300
- -7C sleeping bag $130
- sleeping pad $60
- canister stove $40
- small pot & eating kit $40
- water purifier $100
Looking at this list, going to the high end I'd say its the backpack, tent, sleeping bag & pad that would drive your total cost much higher. For the backpack you could easily go $300, the tent $500, the bag $360, the pad $190. That said a different knife, stove and cookset could easily add several hundred dollars as well. Based on that I'd say the high end could easily break the $2,000 mark.
To go cheaper the couple items that stand out are the tent and the water purifier. Substituting a less expensive (but still quality) tent and water treatment chemicals could easily drop $200 - $300 dollars off the total.