The cheapest 10Gb Ethernet adapter has just landed and it's not that expensive

OWC has started sales of its Thunderbolt 3 to 10 GbE adapter that is designed to add fast networking connectivity to modern PCs featuring Thunderbolt 3 ports. Compatible

 

both Macs and Windows PCs, OWC’s Thunderbolt 3 10G is the cheapest 10 GbE adapter with a Thunderbolt 3 interface announced to date. 

The OWC Thunderbolt 3 10G is based on Marvell’s Aquantia AQtion AQC107S controller that works in concert with as Intel’s JHL6540 Thunderbolt 3 controller (also known as Alpine Ridge). 

Since the product is bus powered, it can work out-of-box, but needs a driver for Microsoft’s Windows. While the adapter can work with all systems featuring a Thunderbolt 3 port, it is not guaranteed to work with all USB-C hosts given the fact that it uses the Alpine Ridge chip.Read more.