Please explain the meaning of the related passages from "The Gift of the Magi" by O. Henry
"...until one's cheek burned with silent imputation of parsimony that such close dealing implied...."
"A furnished flat at eight dollars per week. It did not exactly baggar description, but it certainly had that word on the lookout for the mendicancy squad."
Since O. Henry's stories are set at the turn of the twentieth century, much of the situations and settings are, of course, relative to this time period during which there were small specialized shops in which individual owners ran their businesses. With these privately-owned shops set in neighborhoods, the clientele of such businesses became familiar to the owner and his help. Therefore, since Della Dillingham had almost daily contact with the grocer and the vegetable man, she felt some embarrassment when she haggled with them over the price of their products, for it was insulting to these shopkeepers who were probably generous with an extra chop or bunch of broccoli, for instance. She feared they would think she was just being stingy when she "bulldozed" them. An "imputation of parsimony" means an accusation of stinginess.
Then in O. Henry's description of the flat (apartment) in which Della and Jim live, the narrator remarks that the rent is eight dollars per week. This is a fairly low rent, so although it is not rundown beyond description ("beggar description"), it "had that word on the lookout for the mendicancy squad"; that is, the apartment was very close to appearing to be a place where homeless beggars would dwell. The mendicancy squad was a police squad that picked up beggars and the homeless in the time period of the story. The Dillinghams are poor because in 1906 there was an economic crisis developing, one which was made worse by the major earthquake in San Franscisco.