I looked at the milk you can order through Walton Feed, it has instant for $13.70 and noninstant for $11.60. Rainy Day brand. Walton Feed will have no shipping charges tacked on.
Provident Pantry brand sold at Emergency Essentials.
and the best tasting Non-instant powdered milk is:
Rainy Day brand sold by Walton Feed.
"What is the difference between instant and non-instant powdered milk?
Instant powdered milk is similar to instant rice in that it is faster and easier to reconstitute than non-instant formulas. Typically instant powdered milk takes about twice as much powder per gallon as non-instant, but it depends on which brand you are purchasing."
Read their blog post and find out more.