As you know, choosing a lens depends on what your priorities are. If you're just looking for something pocketable to shoot in daylight, especially if you're just in the experimenting stage, I'd look at the Soviet collapsible 50/3.5s (I-22 or I-50). Fedka is a reliable seller, and you can get a good one from him for well under $100; heck, you can get a FED-2 (probably the best of the Soviet LTM cameras IMHO, and quite pocketable) with a collapsible 50/3.5 from him for under $150. If speed is more important, you're stuck either going with Leica or one of the older Canons (50/1.9), both of which will cost more. Once you move into fixed lenses, your choices open up considerably. Do bear in mind that there is a slight difference between Soviet and Leica LTM RF standards, but this will only manifest itself in any noticeable way with fast 50s or longer focal lengths.