I'd love to be able to own a Lux or Cron but they are way out of my price range unfortunately. Maybe one day I'll save enough pennies to get one and perhaps even an M240 or M9. Hard to justify to Mrs MacRy though.
Get them used; mine are all in flawless - almost new (because I suspect that they were actually hardly ever used) condition but were sold as 'used', i.e. pre-owned - meaning, in practice, that the price was half of what I would expect to pay for that lens new.
Then, to some extent, precisely because Leica lenses hold their value, you can trade up, (and trade in) and you may find - as I did - that the lenses then paid for each other, with some supplementary cash.
Likewise, my M6; that wasn't bought new - I got it used, in flawless condition.
My two Summiluxes were a fortunate buy. I had bought two Summicrons - (a 35mm and a 50mm) - which had never left the shop. I was working abroad in a very unstable environment, and - for the first time in my life - I didn't wish to bring the camera out with me.
Once, while home on leave, I spotted the two Summiluxes (35mm and 50mm) - someone had sold them to the authorised dealer. I phoned him, to check their condition (flawless), provenance (perfectly okay) and to wonder whether he would hold them, and that I would swop them for (initially for one of) the summicrons, and that I would be happy to pay the difference.
I paid just under half of the price those things would retail for new.
However, it does mean that I am putting together a nice set of lenses, lenses that will automatically fit a digital Leica M exceptionally well when I decide to head down that route.