Amazon has the 'Dawn Ultra Dishwashing Liquid, Original Scent, Blue, 14-
Ounce' on sale for $2.67. But there's also a $0.50 off coupon on the page.
Combine that with Subscribe and Save and it brings it down to $1.77 for the
14 oz bottle (with free shipping). That comes out to 0.126 cents an ounce,
which I believe is pretty good...
Link: http://www.amazon.com/Dawn-Dishwashing-Liquid-Original-14-Ounce