Exactly. For those people you don't need a Summicron either.
I've got a couple of adapters for all focal lengths that I bought used. They're all Leica or Voigtländer brand, bought off eBay, all of them good. For a while I had an automated eBay search query that would send me an email whenever someone listed adapters in Europe for less than 20 EUR. I don't think I paid more than that for any of them.