If you have a car and want all the modern amenities like bluetooth connection, here are your options:
- Really old car without auxiliary jack but with tape player. We just sold our car that was literally 20 years old. The only options seems to be either a bluetooth to FM transceiver or to a tape player to aux cable. Neither work super well, the FM transmitter really doesn't work well in urban areas as there are so few clear channels. And the aux cable tends to fail as those 3.5mm contacts are unreliable
- Auxiliary jack. Cars in the mid 2000s started to have aux cables. Here, you want something like Lifehacker's Anker Soundsync. This plugs into the aux cable and connects via Bluetooth LE to your phone. The main limitation is that it does not work with multiple phones. The iClever HB01 (not the HBo1+) is the multiple phone choice.