Frost's "Christmas Trees" may cause the bleeding hearts to screech their revulsion that the city fellow, a businessman, would purchase trees for 3 cents a piece and sell them at a dollar a piece. But that kind of thinking is nonsense. They have no way of knowing the businessman's overhead or how much the trees are actually bringing in the city; after all the speaker of the poem is merely guessing how much the business fellow would sell the trees. That the speaker has a soft spot in his heart for his trees may lead him to reject the offer of 3 cents, but what if the offer had been 30 cents or 3 dollars? Might he have condescended to sell at some higher price? Or what if the seller would buy at 3 cents and sell at 10 cents? Would any of this matter to the bleeding hearts?
Ultimately, all such speculation is irrelevant; it's a poem, not a treatise in economics!