Could you explain the joke for non-Americans?

No joke, really. It's a drugstore/pharmacy that also sells greeting cards, house cleaning supplies, candy, snacks, coke and pepsi and milk, and really low-quality hardware like screwdrivers made of weak steel.

The sorts of electronics they sell there are overpriced and low-quality unless they're actual name-brand items. An LED nightlight sold there is likely to be weak, and badly designed, and overpriced even at $5.

If I saw a $99 Android tablet at Walgreens, I would assume that it would be better to simply burn the $99 - at least then I wouldn't have a useless device to store or dispose of.

(I was just at a Walgreens, and they actually had some Wii units for sale. I wouldn't buy one there, but I assume there's nothing wrong with them.)

I don't know how much there is to explain.

I don't know that Walgreens has that much of a reputation, but I think of them mostly as a drugstore, even though they carry a lot of random stuff. They are a fairly large chain with stores all over the country.

That said, they're not really somewhere you go shopping for high class goods or electronics.

Most electronics equipment sold at Walgreens are of low quality. Its a pharmacy and general store. Most of their electronics are novelties at best.

walgreens was a small drugstore chain. they got national when they started selling alcohol during prohibition as a remedy (exactly like it happens with marijuana in some states now).

nowadays they sell pretty much everything, even prescription medicine in a distant corner :)

most of what they sell is cheap snacks, 99cents products and trinkets.

also walgreens and other drugstores here all have their own brand of copied medicine "walgreens product X. compare to Brand Y product X" on the labels