I always thought powdered milk was a frugal choice. I had a huge box of it and always used it when I ran out of milk, but I finally ran out of it. I decided to buy some this week. I bought it from the bulk foods section at Winco, which is usually the cheapest place to pick up a lot of things (like spices and cream of tartar!).
It was $3.39 per pound, so I got just over a pound and it was $4.17. Many times I can get a gallon of milk for between $2.00 and $2.75 so I thought if I could make 2 gallons of milk with the powdered milk I bought it would be comparable.
I just measured what I got and it was exactly six cups of powdered milk, which will make 18 cups, so just over a gallon. If I pay $2.75 for a gallon of milk it is about $.17 per cup. The powdered milk I just purchased was $.23 per cup!
Lesson learned, I will not purchase powdered milk unless I can get it for less than $2.50 per pound (which makes it about $.17 per cup).