What is the 10 baht tax stamp required for address registration at Thai immigration?

The 10 baht tax stamp is required for registering your address with Thai immigration, especially if your landlord is not accompanying you for the TM30 report. This pink-colored stamp can be purchased at local stationery shops or possibly post offices. While some sources claim this registration process is free, others suggest that there may be informal fees involved, commonly referred to as 'tea money.'