Books on this subject crop up here and there. One of the best was Gamble and Porter's To Market. To Market (Bobbs-Merrill). But this -- for the New Yorker primarily, cuts at the root of the problem everyone is facing today. I say ""for the New Yorker"" advisedly, because -- with the exception of chain stores, the shops used to illustrate his points are virtually all New York and environs. However, the basic principles are there:- how to compare prices and values, how to analyze quality, significance of sales, advertising; how to read price tags. The relative functions of different types of stores, of wholesale houses, of mail order houses, of cooperatives. The author is editor of the Shopping Guide in the newspaper P M.