@MasettoSlothrop If it's low-quality bangin' for scant bucks you're after, I've had surprisingly good luck with this StarTech 7.1 USB gadget.
https://www.startech.com/Cards-Adapters/Sound/USB-Audio/USB-7-Channel-Audio-Adapter-with-SPDIF~ICUSBAUDIO7D
I'm not necessarily RECOMMENDING it - it's only four stereo minis, and I don't know about its input capabilities (as that's never something I'm doing), but for under $40 USD for eight channels, it's been a good purchase for me. I've been perfectly happy plugging my thrift-store mismatched computer speakers in and surrounding myself with clicks and squeals. Supercollider, Pure Data, and Reaper all worked pretty painlessly on Linux, OSX, and (if i remember correctly) Windows 10.