Welcome to APUG.
I'd suggest a Canonet G-III 17. It has a 40mm f/1.7 lens, is reasonably small, and you can probably find one in your price range.
You will need either an adapter or some other means of dealing with the fact that the Canonet was designed to use a type of battery that is no longer available. Most likely, you will also need to replace the light seals as well.
You can find solutions for these two issues in various places, but one of the best is John Goodman, who trades on eBay under the name "interslice".
Good luck, and have fun.