The cost of a PAX/Komplement system certainly can't beat that of the landlord or developer special, which is to say, a shelf above a rod; in my experience, that's always been free. Compared to other closet systems, however, it's a virtual steal. 
When we moved to our place, I knew I wanted to install a customized system and got to work at researching our options. I decided on Italian frosted glass doors, right, and got a couple quotes--one from a famous closet company, another from a local woodworker--for the interiors. The quote for the doors was $7,000; it would be another $7,000 or so for the interior fittings, as long as I was willing to go simple and dial-down my expectations quite a bit. This was for one, 17-foot long closet, the closet in my study. I was crushed.
And then, quite out of the blue, I went to IKE A. I did not go to IKEA for a closet; I went to get a bath mat, if memory serves. And there, on the way to the bath mats, was a dead-ringer (below) for my customized Italian doors. Only they cost $320.00, instead of $7,000. Actually, I would need two sets of doors to fit the space I had. So the savings was only $6,360. 
I added up the cost of the frames--at the time $64 for the narrow width and $72 for the double-wide--and I realized I wouldn't have to scimp on the number of drawers (about $24 or $16 depending on the width of the frame) or pull-out shelves ($24 or $20) I wanted. In fact, I didn't have to stop at my closet. I could knock out every closet in the place--mine, the master, the front hall closet--and install an additional free-standing 8-foot closet to boot--for less than the quote on those Italian doors alone. In all, we spent less than $5,000, including tax, delivery, and installation. And hangers! What more could you ask for?