The Marketplace plugin allows you to find items for sale in vending machines through a nice user interface. Follow these steps:

Type in what you are looking for in the search box or click on the item if it’s already displayed.

You’ll see a list of where the item is being sold (unless no one is selling it).

Click on View and then Set Marker.

Close the UI and open your map, and you’ll see the Shop marked! (edited)