Recently acquired some DDR4 SODIMM ECC RAM. What motherboard should I get?

I received 2x16GB sticks of this semi-uncommon RAM for free and I'd like to tinker with a home server. What is a reasonable motherboard (like under $300) to put this in? So far I've only found a single motherboard that can take this RAM.

Link to RAM & specs:

• DDR4 (2400MHz version)
• SODIMM
• ECC

After scouring Amazon and Newegg this is the only motherboard I can find that will work. And I was hoping to find something even cheaper. The upside is that there's really cheap Xeon CPUs I can stick in it.

• $270 ASRock mini ITX

Anybody have any other suggestions? Or is this my only bet? Thanks.