The disadvantaged farmers face even bleaker prospects as they attempt to sell their household goods and buy vehicles to carry them westward. Fast-talking salesmen, looking to capitalize on the tenants' desperation and naiveté, sell them barely-running jalopies at hugely inflated prices. The salesmen pour sawdust into the engine to cover up noises, and they disguise balding tires. The tenants realize they're being taken advantage of, but unfortunately, have no other choice than to take what is offered.
This intercalary chapter is a staccato monologue delivered by a used car salesman pitching jalopies to dispossessed croppers. Steinbeck's literary technique is similar to the newsreel style popularized by his American contemporary, John Dos Passos. The rhythm suggests the franticness of the situation, a situation in which the salesman has complete control. With the speed and confidence of his words, the salesman is able to fluster and manipulate the stricken farmers, and the repetition of his spiel draws attention to the fact that this was an oft-repeated scenario. Again, this general situation will be specifically realized by the Joads — they need to purchase a car for their trek to California and are exploited by sales tactics they don't understand.
jalopy [slang] an old, ramshackle automobile.
lemon [slang] something, especially a manufactured article, that is defective or imperfect.
carrying charges the costs associated with property ownership, as taxes, upkeep, and so on.