Here is a list of items that are for sale through some Facebook Pages. If you know of any other pages that are selling things, let me know.
Links open in a new window.

Huge High Quality Banners/Flags (Rock Bottom)
Mini Posters/Signs (Leftorium Etsy Shop)
This links to the Etsy Shop with links to the items.
Simpsons Themed Shirts (Four Finger Discount)
This links to a Facebook Album with images of shirts. Click on a shirt and you'll see a link where you can purchase it!