Scale of preference refers to a list of individual wants in order of their relative importance. The drawing of scale of, preference will make it easier for choice to be made.
Since human wants are unlimited and the available resources used in satisfying these wants are limited and cannot satisfy all human wants; human beings have no choice than to rank these needs in order of their relative importance, called scale of preference, placing more important or pressing needs first before the less important ones that may be satisfied at a latter day.
This hierarchicalization of needs which is inevitable as a result of limited resources helps one to make rational choices. For example, a student who is in dire need of textbooks, sneakers, pen, shoes, jean, shirts, book, etc., but with limited resources, may draw his scale of preference like this:
Suppose the student has $20 at hand at the time he needed the above items; judging from his scale of preference above, he can afford to purchase only book, biro, pen and sneakers as a result of his limited available resources of $20 relative to his needs.