Wireless speakers
Bluetooth and Wi-Fi speakers for the kitchen, the backyard and the beach. Sonos and Bose charge the most for the big ones, but small rugged speakers from JBL and Ultimate Ears now fill a room and shrug off rain.
Cheaper alternatives

Sonos Roam 2 alternatives
Three cheaper Bluetooth speakers with longer battery. None joins a Sonos system.

Marshall Acton III alternatives
Three cheaper speakers that add Wi-Fi, a battery, or both.

Sonos Era 100 alternatives
Three cheaper speakers you can unplug and take anywhere.

Sonos Era 300 alternatives
Three cheaper speakers: same Sonos app, retro knobs, or one you can carry.