In Part 1, Chapter 1, of 1984, the reader learns that all male party members are in short supply of razor blades. This is repeated in Part 1, Chapter 5, during a conversation in which O'Brien asks Winston if he has any blades. Winston responds that he does not; and that he doubts if they are still in existence. The reader learns that Winston is lying here: he, in fact, has two razor blades at home but is "hoarding them up" because they are in such short supply. Presumably, Winston was able to obtain these two blades by "scrounging" on the free market.
The shortage of razor blades, then, tell us much about the nature of life under the party. It tells us about the existence of a black market where party members risk their lives by associating with proles in order to obtain the basic items they need. In this respect, the shortage of blades also illustrates the nature of life under the party. By controlling access to certain items, the party is better able to control the lives of its members.
Furthermore, while it preaches about plenty, the party, in fact, deliberately withholds certain necessities from its people, to keep them in a permanent state of dependence.