Is it better to replace my car radio with a Bluetooth compatible stereo or buy a car kit so I can use my phone for music and voice?

What is your question?

I don't really want to put in my own car kit or stereo but I don't know where to start. Who can do that for me and will it cost more to do one or the other? I want to do use my phone for music and voice recognition. And, of course, the microphone. Seeking the most affordable option, the best for the least. Thank you for your assistance.