I took a page from Marcone (one of the short stories) and the priest (another short story) and created this stunt for one of our players:
Buyer of the Arcane (Resources)
You have access to a small number of potions or other single use magical trinkets. You have two potion slots per session. The strength of the item is equal to your Resources skill. You must still use Lore (or a Fate point) for declarations to fill open slots.
I think it's pretty balanced, all things considered. You're getting a lot less than you would with a single point of Refinement.
In your character's case, you could use Burglary.
If you're uncomfortable with them having a number of slots, you could simply make it so that "Once per scene, for a fate point, you may declare that you have a potion or other single use magical trinket on hand." The strength should still be limited by Resources or Burglary or whatever.