As you rummage though the bin you find a hand mirror and look at it in astonishment noticing there is only slight wear and tear to the wooden setting, and the glass hasn't broken. It's not particularly your style, but you are intrigued and take it to the register to ask about it. "Pardon Sir. What does this do." you asked the man who seemed to be looking straight through you.
"Oh!" the man was startled out of apparent contemplation and seemed surprised you were there. Glancing down at the mirror, his face soured. "Bah! That!" He reached behind him to a locked cabinet, pulling down a mirror similar in size and shape. You noticed the price tag was 450 followed by a B... "It's supposed to do this." he held the mirror to the edge of the counter and closed his eyed for a moment. "Go on, look."
As you bent down and peered at the reflection of the counter, you noticed a discrepancy, an elegant ring encrusted with diamonds, sapphires, rubies, and emeralds sat there glistening in all its splendor. You did a double take verifying that there wasn't a similar ring, or anything that could be misconstrued to look, like a ring on the counter. Instinctively you put your hand on the counter and moved your hand over its surface, verifying nothing was there, but as you did so, your reflection did the same, but hit the ring sending it flying through the mirror and into reality.
You jumped back as something shot out of the mirror toward your hand, you made the meekest squeak of terror you think you ever managed to make. Before managing to compose yourself the man inhaled sharply, having run out of breath while silently laughing at your expense. After getting a full breath his laughter shook the store and your face burned brightly with embarrassment.
After both of you recomposed yourselves, he apologized admitting that he meant no offence and would have warned you if he knew you would move your hand so quickly.
"So that's what this does? it makes things that jump out at you?" You held up your mirror trying to bring the focus back to the item.
"Ahh, no. That mirror was modeled after this mirror, and this mirror conjures items from your imagination and lets you reach into the mirror to pull them into our reality. If the ring you summoned was your idea, nobody would question where it came from thinking it had always been yours. And it can hide items in it's alternate reality." He held the mirror up and touched the ring to the mirror, you watched as the ring fell into the mirror clattering to the table without a sound. He gestured to the mirror in your hand "That item, was a failed experiment... it is little more than a magic trick I'm afraid. You can imagine something in there, but can't pull it out. Pretty cruddy for a Mirror of Desired Objects."
"So with that mirror, I could imagine a stack of hundred dollar bills, and grab them, and nobody would question where I got them from?"
"Pretty much. Only works on objects though... can't copy a baby or make a cat." the man said dismissively, returning the 'real' mirror to the locked cabinet.
"So what does this one do?" you asked, mimicking his setup and imagining the stack of bills as you described... You could see the bills, you excitedly reached in and felt them! You snatched them and pulled your hand back but nothing was there.
"Same thing except for actually conjuring the items you see." he turned around to see you looking at your hand with soul crushing disappointment. "The wizard who made that unexpectedly disappeared. Wish we knew what its intended purpose was. Their notes are nigh indecipherable save for 'modeled off Mirror of Desired Objects' which costs a small fortune to make. So it either does only what you have seen there, or it has untold secrets that would be worth a king's ransom to have control over."
"If you want it, its $3. That's the discounted cost of the mirror itself."
At that price you really couldn't go wrong. At worst you have a really cool mirror, at best you could figure out how it was supposed to be used. "Hey, can't you conjure as much money and valuable items as you want, why are you charging me at all?"
The man chuckled, "Magic ALWAYS comes with a price..."
You collected your item and took it home.