$31 from Amazon. Works great.
https://www.amazon.com/Rocksmith-Real-Audio-Cable-Ubisoft/dp/B07RYFWYGC/ref=sr_1_1
The easiest option is the Rocksmith Real Tone cable. It will work out of the box with no additional software, and typically minimal configuration. https://www.amazon.com/Rocksmith-Real-Audio-Cable-Ubisoft/dp/B07RYFWYGC