There's a city. It houses just over 200,000 people. What's special about this city, is that it's the only city.
About nine kilometres from the center of the city, in all directions, is a fog. Any roads that lead out of the city will inevitably somehow lead back into the city, and going off road has as much success. There is no known way to truly escape the foggy event horizon.
Twice a month, a traveller with no memory will wander into the city, and any writing they have on them will be distorted and unreadable. They cannot leave through the fog, and they start with nothing magical.
The city has an abundance of domesticated animals, farms, quarries, mines, clay pits, etc.
It also has access to a lake, mountain, caves, forests, and various supernatural dwellings. The tech level is medieval-ish, aside from items relating to the true subject of this question.
The true subject of this question is the peculiar phenomenon that occurs in the city. When a person grows a strong attachment to a material possession, it may eventually gain mystical properties.
These properties will often vaguely relate to the thing they were used for, but with a twist. A much-loved book may change genre to match the reader's mood, a rope may coil automatically, a mirror may show no people whatsoever, only the inanimate objects behind them and the background, two matching rings may make nobody find the wearer attractive except the bearer of the other ring, a favoured pencil might change the scription to the way a pirate would write.
These changes are usually benign, occasionally useful, and often subtle enough to go undiscovered for months, sometimes years. They will not usually make the item more durable, and usually never have effects that are quite the same as a past object.
They are sometimes stolen by magical creatures, accidentally broken, and are occasionally instructed to be destroyed by their original owner in their will. There is usually about one of these per two people.
More interesting, however, are items that are used communally or by an organisation. These will tend to take on more specific, elaborate, and purpose-focused effects.
These include a bell that only the desired servant can hear, a waste bin that destroys any inanimate object put inside it, a pool that turns non-organic substances into copper on contact, a keg that will turn beer into a practically infinite number of different liquids, depending on how the three dials are turned (pear brandy, syrup, tar, lime perfume, blood, olive oil, nitric acid, saliva, brine, mercury, etc.) or a book that will erase crossed-out words, remember what was written on torn out pages, or even in dreams or other timelines as long as paper is placed in its position.
These are rarer, and there may be one per fifty people.
This likely creates a culture of holding onto things.
Prices of resources that can easily be created with items will likely decrease significantly.
But my question is more focused on how the economy deals with the abundant magical items themselves, not how this affects industry.