Audio input for new MacBook Pro

I’m planning to upgrade from an Early 2011 MacBook Pro to a current model. Does anyone know of an inexpensive Thunderbolt 3 dongle I can use to send audio input to the Mac? On my present MacBook Pro I can just use a 2 RCA to 1/8” stereo plug adapter. That hooks to the Tape Out jacks on my home stereo. Nothing fancy. All I can find so far is pricy boxes. Surely there’s a cheaper way?

G’day Steve

I’ve happily used a Griffin iMic for many years ( Maybe run it into a USB A to USB C/Thunderbolt cable?

Cheers, Gobit