Folders with rangefinders tend to be quite expensive, but accessory rangefinders can be found cheap, and learning to scale focus is a good exercise (it actually isn't all that hard if you aren't close up or wide open). I'm a fan of Nettars, which are basically low-spec versions of the Ikonta---they're dirt cheap and they were built like tanks.

And yes, TLRs are profoundly wonderful. The most common good ones in your price range seem to be the various flavors of Yashica; you might score a Rolleicord as well. Either is capable of excellent performance. The Mamiyas have a fantastic reputation but I've never shot one personally.

-NT