Cost: 25sp
This kit contains parchment, a variety of inks, quills and pens, some blank seal rings, sealing wax and everything else you need to create a forged document. Possession of this kit is widely viewed as suspicious.
Each document that you forge with this kit will consume 5sp worth of its value, so the kit effectively has five uses. Once it's consumed, you will need to purchase another. You can also spend 5sp to purchase replacement supplies.