I was looking online to try and help you find a good adult diaper for the best price and while I do not know what they usual go for I was seeing them for around $80 (ouch) - then I found this site, were they are $50 for extra large with FREE shipping... smaller sizes are less.

http://astore.amazon.com/cheap-adult...ng=UTF8&node=7

http://www.yourdiaper.com/prevail-br...012-p-190.html