Cheap digital I/o for vst system link?

Hey folks,

I’m interested in hooking my laptops together using VST system link.

I already own plenty of high end audio hardware but it has been left behind in my studio.

I want to buy 2 cheap USB audio devices that with both receive and transmit digital audio for the system link.

VST system link works with a single digital audio out to in and it can be coaxial or ADAT digital.

Anyone know of something in the 20-50 dollar range that will be reliable?

Thanks for the help!