Mpow Bluetooth Receiver/Transmitter with SPDIF/AUX/RCA Connections | $18 | Amazon | Promo code MPOWBH108
External Bluetooth transmitters and receivers with 3.5mm jacks have been around for years, but this model from Mpow raises the bar with support for optical (SPDIF) audio.
The little puck can both receive and transmit Bluetooth signals, and includes SPDIF in and out ports to connect it to your TV or high-end audio equipment. You can also connect it anything with RCA or 3.5mm outputs too, which ought to cover just about any audio device in your home. Just be sure to use promo code MPOWBH108 at checkout to get it for $18.