You can also buy Walmart brand of Ensure it has all the same protein and vitamins and it is much cheaper or any other off name brand. You just won't end up paying for the nice packaging and the big name.
I think a product like Carnation Breakfast Essentials Nutritional Drink powder, mixed in milk would provide similar nutrition. Walmart and club stores carry it at lower prices than grocery stores.
One can also make a homemade equivalent of Ensure for quite a bit cheaper and often even healthier as they don't contain as much sugar. Google, and you will find recipes often including protein powder, milk, egg, yogurt, etc you can get cheaper at Walmart. Not as convenient of course, but can be a lot cheaper. At least you can do that sometime so that the amount of times you need the real can for convenience reasons is less. Costco also has a store brand much cheaper. My mom said it didn't taste as good, and maybe shes right I don't know. On one hand, who cares, on the other if an elderly person doenst like it they wont drink it as much as they sould.
There are also coupons for Ensure in your Sunday paper that you can use.
I have been told that Costco and other places like it have Ensure sold in cases. I have heard some who say this is the best price.
I also see Ensure on sale a lot at the major drug stores. I would look for these sales and stock up.