start with 1980's walkman headphones laying at the bottom of the closet in a tangled ball of wires, in an illegally obtained milk crate, that havent seen the light of day for a decade. pop off the speakers from the frame and peel off that sticky foam.
now take the green walkman headphone input off that old diskman that didnt work anymore because the headphonejack broke off its solder points and found itself in the same crate. easily pull connector off the pcb.
random wire from same ancient crate
electrical tape
double sided tape to stick speakers in your preferred location
and a male to male stereo wire also found in the same crate

cost... physical labor looking for crate of wires in the bottom of the closet =x

used white wire stuffed in the groove of the padding around the back rim of the helmet for the left ear.

 

Regardless of the fact that my exhaust can wake the dead and set off car alarms, I always wear foam ear plugs. I did with my previous bike (ZX1100 with stock exhaust), so it's not a noise thing.

The first few times it seemed so strange, but once you get used to earplugs, there's no going back.

On longer road trips with lots of interstate riding (boring) I listen to music, but not around town... Crashed my last bike riding through rush hour traffic and spacing out to pink floyd. Nobody hurt, bike totalled, lesson learned. Never again.

On the highway it has the opposite effect for me - keeps me awake and alert when 300+ miles start to make you drift away.

Honestly, try everything, and see what works best for you. No such thing as bad experience.