This plan has many advantages over a “free” offer. It is much more impressive, for one thing.

There is a considerable difference in the psychological effect when you offer to buy an article for a woman to try, and pay the dealer his price for it,as compared with offering that article free to all.

The “free” offer cheapens a product.

There is a certain resistance when we ask people to afterward pay for a product which came to them first as a gift.

-My life in advertising, p.85