I don't know. I know the amateur crowd likes them. I've got several of the 146MHz to 174MHz versions, and I've had no issues at all getting them to TX down around the high 144MHz range.
Unless you really need something down below 2 meters, I wouldn't pay more for a 136 version over a 146 version. The 136-162 versions do seem to be rare. Other than some military use, not much reason to go below 150 MHz for most public safety/commercial use.
As for price, I wouldn't pay more than about $25 for one of them. There were thousands of these replaced for the narrow banding work, and they are all over the place. I know there are some guys on e-bay that seem to think they are made out of solid gold. Some careful shopping around should find you a good price.
I got several of the 16 channel versions for free a few years back. Good solid radios. We use them on the 2 meter band on ATV's and UTV's. Other than some risks with water intrusion, they've stood up well to the vibrations. Newer radios (like CDM's) seem to have better sealing, but this likely won't be an issue for you.