I am somewhere in the $3000 to $3500 range. It's a lot more than I expected. I don't have all that many, just three centerfire rifles, a rimfire rifle, a blackpowder rifle, two shotguns, and four handguns. I'm in the process of building my first AR, but I didn't count the $150 worth of parts there. I also have about 5k rounds of various calibers and probably $300 worth of powder, primers, and bullets for reloading.
What restrains me is lack of time or facilities for shooting. If I move to the country or close to an outdoor range, I'll probably add a bunch of guns.
Chris