Comparing the price of the 22mag to the 17mach2,The 22mag isn't any cheaper from the sources that I checked.
http://www.wholesalesports.com/storefront/home/hunting/ammunition/rimfire/c0-c10-c102-c10202-p1.html
Your right, I stand corrected. I used to buy the cheapy Winchester stuff for about $7 a box or somthing like that. I called Wally World a short time ago and now it's $9.50.