Hook up iPhone to boom box wirelessly!

http://www.iphonefmtransmitter.com/music-transmitter-for-iphone-6-iphone-6-plus/

This is by far your cheapest option, with auxiliary cables running about five bucks.

Check your current car stereo to see if there’s a little hole on the front of it that looks like a headphone jack, as plenty of stereos from the mid-90s and onward sport this feature.

If you’ve got such a jack, then pick up an auxiliary cable, plug one end into the jack on your stereo and the other end into the headphone jack on your phone.

You may need to switch the input on your stereo to “line in” or “AUX” or something similar, and it’s probably done the same way you switch between AM, FM, and CD modes. Check your stereo manual for more info, and by “check your stereo manual,” I mean to Google it, of course. That thing is looong gone by now, right?