Treasure: Ring of Protection
A staple of all fantasy treasure piles is this simple magic item - a ring of protection. I used it to see the price differences between different enchantment systems - Sorcery, spell-less Sorcery (when you simply enchant the advantages required without using a predefined spell), and Metatronic Generators (from Pyramid #3-46). You can see the Armor spell in GURPS Sorcery - Protection and Warning Spells.