At the moment, I don't think Leica prices are appreciating, at least not in the UK. Certain lenses are, but not the bodies. I have never bought any camera on credit, but if you're going to, a Leica (film) camera is a decent enough thing to buy. They likely will not increase, in fact, they'll likely go down in value, but nothing remotely like digital, and if you're a user, not a collector, the use you'll get out of them for the money is extremely good.
I bought and sold a Leica MP for about the same amount of money, so basically I had the use of one for a few months for free. If I'd decided to keep it, and use it for say a couple of years, I'd have added a few nicks and scratches, maybe knock £100 off the asking price, which is amazing for a couple of years use.