OnLogic's N3350 pico-ITX motherboard now $145

"PICO-ITX PERFORMANCE The Pico-ITX form factor measures in at a tiny 100 × 72 mm (3.9 × 2.8 in), combining an ultra small form factor with reliable performance. The EPM160 hosts an Intel Celeron N3350 processor with dual cores and Intel HD 500 graphics. The Apollo Lake generation offers up to a 30% performance boost over systems running on previous generations, featuring low power consumption and reduced heat production.

COMPACT SIZE, VERSATILE I/O The EPM160 motherboard is ready to connect, featuring two USB 3.0 ports, one USB 2.0 port, Gb LAN port, and one mini-DisplayPort capable of 1080p or 4K resolution. In addition, the board offers a 9 pin RS-232 box connector COM port and a MicroSD Card slot for customizable storage. 

EXTENSIVE EXPANSION Featuring both a full-height and half-height mPCIe slot, the EPM160 can support an extensive range of expansion card options with ease. Up to 1 TB of storage may be added through a mSATA slot (shared with the full-height mPCIe) or using the MicroSD Card slot."

USA https://www.onlogic.com/epm160/

Europe https://www.onlogic.com/eu-en/epm160/