If you're looking for portability and reliability, but can eschew using a meter, then a Kodak Retina IIa is very hard to beat, once they have been serviced. A Leotax K or Fed would be a great small rangefinder as well.
After that, take Kostya's advice and look it up on ebay. You could do a lot worse than invest a bit more and pick up a camera like a Pentax MX with 50mm f/1.7 lens, or Olympus OM-2n with a similar lens. Both are the size of screwmount rangefinders, have excellent meters, can be repaired into the 23rd century, and are extraordinarily reliable.
The days of the working thrift store camera at a thrift store price are long gone. I regularly see Olympus XA, Canonets, Nikon L35AF go for up to $200 USD on SGW, so you're simply not going to find them unless you have a relative who wants to give you their gear.
If you have to have a light meter, get a Gossen Luna Pro, the Gossen battery adapter, and use it for the rest of your life. You're not going to find a rangefinder with a working light meter for a bargain. You *might* be able to find two of those three criteria, but no longer all three in one camera. These days, all the fixed lens, compact rangefinders or point and shoots should be considered disposable, unless a person is willing to put some real money into getting them serviced. None of them ever had a great light meter to begin with, only decent when they were brand new.
Phil Forrest