Kramer and Newman hatch a scheme to arbitrage bottles from NY, where the deposit is 5 cents, to Michigan, where the deposit is 10 cents. They can't figure out how to make the costs work; gas is too expensive (variable costs), and there's too much overhead (fixed costs of tolls, permits, etc.) with using a semi to haul the bottles in volume. Finally, they hatch a scheme to use a mail truck, which lowers their variable and fixed costs to zero.
Jerry does something nicer for his dry cleaner, who then extends his family a discount. Jerry's girlfriend claims to be his wife in order to get the discount.
George asks Lupe, the maid at his hotel, to untuck the sheets at the foot of his bed, because he can't sleep if the sheets are too tight, George is disappointed in Lupe, who didn't untuck his sheets as she had promised. Jerry asks George if he remembered to tip Lupe, but George forgot (no incentive after you're gone and if you're not coming back). Jerry says, "That's why communism failed."