While my kids were at school, I did a little math of my own to figure it out. The exact cost will vary depending upon how much you pay for each ingredient but I will break down the cost according to prices I have found this fall, 2013. Online prices tend to fluctuate often so like I said, this cost will vary.
NetGrocer.com has a sale right now of $20 off $50 with the code NETGROCER (which basically pays for shipping) and Bob's Red Mill is on sale for 50% off. (Please note these ingredients may be made in a facility with one of your allergens. Please contact the manufacturer as always to make sure the products you use are safe for your needs!)