I have ordered Mountain House direct from their factory. You can put in your order at their website:
http://www.mountainhouse.com/If you're buying them to use soon, you might find a better deal somewhere else online that has old product, because they probably discount things getting closer to expiration. From the factory, you're always getting new product, so it'll have a longer shelf life for things like your emergency supplies.
Fyi - If you're associated with the Boy Scouts, they are very nice about discounting case lot purchases. <img src="/images/graemlins/smile.gif" alt="" />They just need you to fax a copy of your unit charter to them before you can get the discount.