Hello,
I've got mine for a factory fitted blaupunkt in my non-fiat daily car from aliexpress. Two versions were available: with or without the microphone for hands-free phone calls. It costed something like 6 or 8 USD. The installation is easy if you have basic technical skills and have a special tool to take the radio out. I saw that some sellers offer this tool with the bluetooth kit. The sound quality is very good.
The idea is to be sure which connector will fit your setup and order the correct one.
If your radio is working without the ignition on, the bluetooth kit will also be powered all the time. You can think to connect its power through another fuse (that works with ignition on only) or add a small switch somewhere on the dashboard, especially if your battery is a little weak or you're not driving on a regular basis, as it could drain the whole battery out.