Heroes of Loot

Titanium Shields are sold in stores for 250 coins. The store items are random each dungeon so it is worth checking each one. If you have enough money, this is worth purchasing for the trophy. Otherwise I would recommend avoiding shields, as they are not worth the money so you are better off saving for the Cup of Life and Lens of Secret items.

Note that Titanium Shields are sometimes awarded for completing Quests. I had the trophy before earning one this way so I am not certain if the trophy will pop only by purchasing it from the store or if being awarded it from a Quest also counts.