I've picked my first lock, where do I get more?

I've picked a master lock (3 I believe). I also picked all the little cylinders that came with the lockpicks I ordered. Sparrow progressive. I even respinned one... Mostly due to accident.

Where do I get more locks? I think I just need the cylinders. What are these called? Where do I buy them from? I'm mostly looking for cheap and they don't have to have a practical purpose. I'm just wanting to pick them for kicks.