Announcer: In the opening credits, what does the cash register say when Maggie is scanned?

Announcer: In the opening credits, what does the cash register say when
Maggie is scanned?
The cash register says, "NRA4EVER", just one of the hundreds
of radical right-wing messages inserted into every show by
creator Matt Groening.
Troy: Over the six years "The Simpsons" has been on the air, we've
received dozens of letters from fans wanting to know more
about the show. Tonight, we'll answer some of your
questions.
Professor Lawrence Pierce of the University of Chicago
writes, "I think Homer gets stupider every year." That's not
a question, Professor, but we'll let the viewers judge for
themselves.
-- No jury in the world would convict him,
"The Simpsons 138th Episode Spectacular"