(Strip Number 3990, Original Publication Date, 17 April 1981)
Panel 1: As Elly takes the lid off a pot, she thought-bubbles "'Our money' really is his money; I don't earn a cent." This is, of course, wrong; John earns his money for the use of his family first and foremost which makes it 'her' money too.
Panel 2: As they shovel her tasteless mush into their gaping pie-holes, she thinks to herself "I know that that's the wrong attitude. There must an obivious way to prove my monetary worth." This panel seems to me to be the answer to the question "What is Elly really sore about?"; since she doesn't earn money being a SAHM, she feels that what she does is worthless. The stereo is simply a "reminder" that since John has money, he can do what he likes while she's stuck opening cans by hand.
Panel 3: We next see John compliment Elly thusly: "That was *BURP* a great supper, Elly."
Panel 4: Her telling him "Fine; that's $15.95 with the tax and
Summary: This strip seems to me to be little more than fodder for arguments and disharmony. While it's true that what she does do does have value, it's sort of equally true that neither of them are quite willing to admit it. John, for instance, seems to think that she's built to do this sort of thing without complaint and never quite realized that she felt, well, inadequate, that cooking, cleaning and child-rearing weren't enough of a contribution. She never thought that what she did had social value; he never thought that it deserved any greater monetary compensation than the spending money she never believed she had enough of.