Aside from the board, you also need a power supply with a micro USB connection, capable of 2.5A of output (realistically, you can use a smaller supply, but 2.5A

Aside from the board, you also need a power supply with a micro USB connection, capable of 2.5A of output (realistically, you can use a smaller supply, but 2.5A means you shouldn't have to worry about power limits). You need a MicroSD card at least 8GB in size, although larger is always nicer. Since it's the main storage for the device, faster is better. An ethernet cable, if you don't plan on exclusively using wireless. A case: the Pi3 is the same layout as the Pi2, so a previous-generation case will be fine. An HDMI cable, if you won't be using it exclusively headlessly (or a cable with TRRS on one end and red+yellow+white RCA connections on the other end, if you're going the analog route). A USB or bluetooth keyboard and mouse. That would be my shopping list, if I didn't have those things laying around at home.