The short answer is "it depends."
Here's the long answer: The papers I use most frequently are Arches HP 90 lb and 140 lb. At Dick Blick right now they're $4.19 and $4.83 per 22"x30" sheet. I keep my eyes (and inbox) open for specials, especially the free shipping ones, so I end up paying less, but let's say $4.50 a sheet. I use 2-1/2 sheets per recipe that calls for 5 grams of silver nitrate. I get eight to ten 8x10-inch sheets, plus enough selvage for test strips (or a lot of 5x7 pieces.) That comes out to $11.25 for paper and approximately $5 for silver nitrate = $1.50 to $2.25 per 8x10 piece of printing paper).
Beyond the one-time cost of the tools, paper and silver nitrate are the only real expenses. Depending on what you can raid from your kitchen, and how many of the items I listed you might need to talk to Santa about, (http://thelightfarm.com/cgi-bin/html...tent=02Dec2012) the equipment costs to start up will range from zip to less than $250. Since you need some of the tools and materials even if you're printing with commercial paper, how you count those costs is an individual matter, as is your philosophy of amortization.
Another factor in determining cost is the value you place on time. Making your own materials isn't "efficient" in the sense we've all come to expect efficiency. No craft is. Having said that, basic paper pulls together really fast. If you don't count drying time, I spend less time per recipe than I do making a loaf of bread.
Last but not least, as you hinted, what price satisfaction, or heck, just plain fun?
Hope you give this a try!