Book where a pickpocket steals a sorcerer's stone and becomes his apprentice

Question

I am looking for a book where the sorcerers bond with special stones to use their magic, and the main character unknowingly steals a sorcerer's stone, almost dies from the stones power, and is saved and made that sorcerer's apprentice? The main character is a street boy, and the sorcerer teaches him to turn into a black cat, I think. He eventually breaks into the Palace and tries to steal the queen's necklace, because it is his stone. The sorcerer is disgraced and lives in a half-destroyed castle.

I remember that when the main character was pick-pocketing the sorcerer, he says something like "If he can pay to be snooty, he can pay for my lunch." (not exact).

I can't remember any more than that, and the book seems to be from several years ago, in the early 2000's.

Answer 1

This is likely The Magic Thief by Sarah Prineas.

In a city that runs on a dwindling supply of magic, a young boy is drawn into a life of wizardry and adventure. Conn should have dropped dead the day he picked Nevery's pocket and touched the wizard's locus magicalicus, a stone used to focus magic and work spells. But for some reason he did not. Nevery finds that interesting, and he takes Conn as his apprentice on the provision that the boy find a locus stone of his own. But Conn has little time to search for his stone between wizard lessons and helping Nevery discover who or what is stealing the city of Wellmet's magic.

Looking at the excerpt on Google Books, this may be the line you're thinking of:

His purse, I decided, would be paying for my dinner, though he didn't know it yet.

I came upon it with the search terms of novel boy steals sorcerer's stone becomes apprentice after scrolling past some Harry Potter results.