There are these Velobörsen on certain days in school yards and squares and those kinds of places where you can pick up a rusty suicide machine for 80 CHF or something a bit more secure for 120 or 160 CHF but I think they are usually more common in spring and then autumn. If you do a www search for "velobörse Zürich" you might find something.

Hey Natalie

I have been looking for a new bike but have found renting the local bikes for free a great alternative.  

Check the classified section here at glocals (goods for sale section). I find that there are a lot of people selling their bikes.

Hi, there are two shops I can recommend:

http://maps.google.ch/maps?f=q&source=s_q&hl=de&q=Veloladen&sll=47.381512,8.496616&sspn=0.002811,0.009645&ie=UTF8&split=1&rq=1&ev=zo&radius=0.27&hq=Veloladen&hnear=&ll=47.381512,8.496616&spn=0.002811,0.009645&z=17

The first one is  marked onmap, buit the second one is just in that lving block like 50m from Kindergrippe Gummibärli. I think, that one is the best for used bikes I ever spotted in CH. they have cheap to expensive ones. City Bikes, Tandems and Mountain bikes for moderate prices (relative to CH). As I will still go jogging this eve, I will check out the right address and post it.

:-) Cheers,

Franziska

Hi Franzisca! Thanks a lot for your post!

I'try to go next week and then I'll let you know!

cheers

Martin

http://www.provelozuerich.ch/leistungen/veloboersen

saw some 2nd hand bikes in Helvetiaplatz market (I went on Saturday around noon)

and also in a brokenhaus located next to Albisriederplatz, from Albisriederplatz you take badenerstrasse, it's number 399 I believe, just above this shopoutlet thing (2nd floor). They sell loads of 2nd hand stuff btw, not only bicycles.