Sorry for the crash too...
Your lil ones are really cute by the way ;-)
I can't help you with coupons since I have a lil one the same age as yours but have you tried
www.1800diapers.com
They are competitive with prices and I can refer you to get a discount on your first order. The best part is they deliver so you don't have to carry those big bulky boxes ;-)
Costco is also probably the cheapest place unless you live near a military base and can get someone to go on base and buy you some.
Try going to enfamil and similacs pages and registering. They usually send a free sample and coupons monthly. Usually a buck or two but that adds up when you are buying as much as you are most likely buying.
Good luck to you. I have 3 but only one that little and I can't even imagine how hard it is to have to have 2 9 month olds cruising around :-)