wow - that's not quite how it goes in Aveyond, but I know what you're asking.
You need a tileset that has a table in it, so place the table. Then put an event on the table that has 2 pages. First page has no preconditions, and in the graphic you place the image of the birdcage that you want displayed there (you might have to find an image for that too). Have an Action Button trigger to give the option to buy it, and if player chooses yes, set a switch (not a self-switch) on. Then in the second page, have that switch as a precondition, and no image. So first time through the cage will appear on the table. Player inspects it, has the option to buy. If they say no, switch stays off and birdcage stays on table. If they say yes, switch goes on and birdcage disappears (in that choice handling you'll also have to do the money changing and item changing so player pays for and receives the birdcage). Then anytime they come back to that shop, there's no birdcage because they've already taken it.