FWIW, the click stops on the 25/4 are great and I love using this lens, but this point is kind of off-topic as this thread is really about the 35/2.5 Classic, a great lens.
I figure the 35/2.5 should sell for about $150 used in good condition. It's $209 new on the Cameraquest site (which is a great price). Note that it is thread-mount. If you want to use it on an M-mount body, you'll need an adapter which will cost $55 new.