My recent new to me car (a Civic Type R hatch) came without a stereo head unit in it, but some speakers of unknown origin.
I was quite prepared to be buying a head unit and a full set of speakers, and almost pulled the trigger on a really expensive set, when a little voice in my head said "just put the stereo in and see first!", so I did.
The speakers are phenomenal. Some kind of custom set with Hertz components, they really are awesome.
So, I found a really nice set of speakers, although technically they were already my property.