"Hey, you been in the dungeons recently? Looks like someone's set up a shop selling cheap magic items down in a lot of them. You should check it out, maybe they've got something worth the trip."
That's what your friend told you that got you down here. Now, after making your way through a number of monsters and traps you'd rather not dwell on, you see it before you: a brick and mortar shopfront standing in stark contrast to the ancient stone surrounding it, clean and brightly lit despite the darkness and grime all around. A sign out front advertises "Half-Price Magic Items - Always On Sale!" with a mechanical construct waving a sign around pointing to the entrance.
Well, you've come this far. You step through the door, finding tidy and organized shelves with more mechanical, humanoid constructs - one sweeping the floor while another stands behind the counter, drumming its metal fingers on the clean, polished wood surface. A somewhat conspicuous door is set into the wall by the end of the counter. The constructs pay you no mind as you peruse the shelves, save for the one sweeping up avoiding bumping into you. You notice they're out of the one thing that has a name that has caught your eye, a wand of illumination.
Stepping up to the counter, the shopkeeper-construct's gaze moves from staring off into the middle distance to looking at you, suddenly at attention. "Ah, how can I be of assistance?" it asks, its voice tinny and sounding like a poor quality recording.
"I'm interested in a wand of illumination, but it looks like you're out of them," you reply. It's probably just an automated store, a few have popped up in larger cities as of late, but not in out of the way places like this. You've gotten somewhat used to the way they operate.
"Well, I can't leave my counter, you never know when a customer might come in!" it says, gesturing to the otherwise empty store. Definitely automated, you think to yourself. "But, if you'd like, you're free to check in the back." The automaton gestures to the conspicuous door, its somewhat dusty frame standing out against the otherwise immaculate surroundings.
With a shrug, you approach the door. You notice out of your peripheral that the counter automaton lacks legs, instead being attached to a metal box bolted to the floor, but that's pretty standard for such automated shops, so you continue through the door.
What you find in the 'back' of the store is mostly what you would have expected, boxes on boxes with labels scrawled in some unintelligible script. However, looking past the stored merchandise, you see a hallway. Its walls and floors are polished wood, the ceiling made of some sort of stone. It grows darker as it extends deeper into the space, fading into an inky black in the distance.
Looking away from the hall for now, you glance over the boxes and quickly find what you were looking for - a wand labeled with a little tag reading "illumination". flipping the tag over, you find that it not only casts a light before you, but apparently is meant to help you find your way when lost... somehow.
As you're about to head back out through the door and make your purchase, your curiosity gets the better of you. You turn, and stare down the dark hallway. Muttering the activation phrase to the wand, it shines a light before you, and you venture into the darkness...
...
Some weeks later, in the middle of the nearest city, a crazed-looking adventurer bursts out of the back storage room of an automated shop. Apparently, they'd found a store in a dungeon and went into its back storage area, and somehow gotten lost and ended up here. They were clutching a wand that was later found to have a misdirection curse on it, turning them around and getting them hopelessly lost.