DealKings via Amazon offers Prime members the Shower-Mate Portable Waterproof Bluetooth Shower Speaker in Black, Green, or White, model no. S4, for $12.99 with free shipping. (Non-members can spend $35 to qualify for free shipping; otherwise, shipping costs $5.74.) That's the lowest total price we could find for such a speaker by $2, although we saw a similar speaker for $3 less last month. It features a built-in mic with speakerphone and a suction-cup mount.

Also available is the Shower-Mate Portable Waterproof Bluetooth Shower Speaker with Hook Handle in Black, Red, or Blue, model no. M5, for $14.99 with free shipping for Prime members. That's the lowest total price we could find for such a speaker by at least $2.