Amazon offers Prime members the Sabrent WiFi Audio Receiver, model no. WF-RADU, for $29.99. Coupon code " 7NTWFHB7" cuts it to $22.99. With free shipping, that's $27 off list price and the lowest total price we could find. (Non-Prime members can spend $35 or more to qualify for free shipping; otherwise, shipping adds $5.19.) It allows you to connect your iPhone or other smartphone and stream to any home, car stereo, or wireless speaker system. It also supports DLNA and AirPlay.

Update: This is not Bluetooth-capable, as originally noted. We apologize for the error.