How can the UI "ask" for a certain object

Hello everyone and thanks upfront for the support! I'm trying to build a simple shopping game and for the first prototype I want something very simple in concept, but I keep smashing my head against a wall when it comes to the code. Basically, what I'm trying to obtain is as simple as this:

1. That the name of a gameObject Prefab (E.g. "Banana") appears in the UI and thus the UI would be "asking" you to buy this object.

2. That you place the Banana in a certain area (know more or less how to do this, with OnTriggerEnter) and then the UI "detects that" and displays something like "you bought a Banana" in text

Would be also pretty happy if you had any links to tutorials for games with similar mechanics where the game "asks" you for an object from time to time (such as overcooked) and you need to provide it.

Kind regards and happy development!