In "Stamps" by Bethlyn Madison Webster, I believe the symbolism is found in the title and the several occurrences of the use of the word "stamp" throughout the poem.

Literally, the first stamps are "food stamps," which are given to people who don't make enough money to be able to eat properly. There is a certain "stigma" with some people about those who need food stamps, along with deep-seated embarrassment by those who use them. It is a sad commentary that the check-out clerk thinks she has the right to study the food on the belt in judgment, and even sadder that the speaker of the poem feels the need to apologize for needing the stamps.

I think she wants
to see how her tax dollars 
are being wasted today...

The second use of stamps is the "rubber stamp" that the cashier uses to count the stamps presented. I can only imagine that the stamping makes noise, announcing with each stamping motion that the tickets are not just being counted, but voided—the sheer act delivered with emotions similar to anger, resentment and censorship.

The checker lays the coupons upside-down,
like a blackjack hand,
and pounds them with a rubber stamp.

However, figuratively, I find that the idea of "stamps" in this poem points to what we often term as a "stamp of approval" or "the Good Housekeeping" stamp (or seal), both of which express acceptance and merit. There is nothing about the cashier's attitude to show sympathy, compassion or approval. If living a life making only ten cents above minimum wage, with a child to support as well, isn't difficult enough in itself, it is conscionable that the woman at the register also feels it her right to also be critical and selfish in her nature.

The poem speaks to the audience to point out the hurtfulness of judging, the lack of compassion some people demonstrate, and the need to draw attention to another person's difficulties in life.

The stamp symbolizes the pain and embarrassment of needing to ask for help, the censorship delivered by the uncaring cashier, and society's sense that the situational details of someone's life somehow summarize the value of that person's life, which is totally inaccurate and extremely unfair.

What is the theme of the poem "Stamps" by Bethlyn Madison Webster?

The tension in Webster's poem "Stamps" is between the shopper who looks back at the woman and her husband and child in line at the grocery store.  The shopper inspects what the other family is buying because they have food stamps, public aid for which the shopper's salary deductions are made.  Critically, then the shopper eyes the chocolate that the family is buying since candy is not an essential food.  Obviously, the shopper feels insulted that her "hard-earned money" should pay for candy.  On the other hand, the woman is humiliated that the shopper should feel the right to inspect what they buy because they do try to support themselves, but the salary falls short of subsistence level.  In further degradation, the family has their food coupons turned over and rubber stamped, thus making the tender less than money and clearly nothing that they have earned.

So, the theme of this poem can be stated in terms of the "stamping" of people, labeling them all as shiftless, who must use government aid.  The woman who is so labeled feels shame and humiliation; she wants the shopper to know that they do work, but what they make is not enough to support a family.

Explain the metaphor in the poem "Stamps" by Bethlyn Madison Webster.

In "Stamps" by Bethlyn Madison Webster, the book of foodstamps become a metaphor for the class division of the woman, her baby, and husband against the woman with the "Cheerio" mouth and pink fingernails who purchases rib eye steaks.  As the husband pulls his public aid stamps from his pocket, the woman hastily grabs her purchases and glares at the food that is to be purchased with these food stamps which represent the tax money deducted from her income for public aid.  She haughtily sneers at the chocolate, thinking that the people do not need this.  Thus, with their food stamps, the three people become to her the lower class whom public aid, her tax dollars, support; they are despicable, lazy people who do not deserve chocolate or potato chips.