Here is the RPi4 for $99.95 with power adapter, case and card.
American Raspberry Pi Shop. One stop shop for all your Pi needs. Raspberry Pi add-ons, HATs, accessories, Starter Kit, Media Center kit, RetroPi Arcade kit, Ultimate Kit, and many other project kits. PiShop.us is approved Raspberry Pi re-seller and carries all official Raspberry Pi boards and...
www.pishop.us
Moode is available here:
moodeaudio.org
Flash Moode to the card, insert into Rasperry Pi, attach an ethernet cable and setup the unit for wifi with your login data. With a few clicks setup UPnP, Airplay, or Spotify. Start streaming with Audirvana or your favorite player. It's that easy. I can typically setup and configure a new RPI-4 in 10 minutes.
Wifi signal is available throughout most locations while RF signal typically is line of sight only and can easily fail in a short distance. RasperryPi offers much more flexibility, range and function. RF extender TV boxes were all the rage 20 years ago. Now they are considered mostly junk. There's a reason for that.
If you have a mental barrier that setting up a RPi web based configuration is too hard get a Wiim Streamer for $99.99
Both of these options are better than any RF device.