The questions is too broad. You might get lucky to find a bedroom in a smoky shared unit, for 600CHF/month, but you could pay as high as 3000CH/month for not much in terms of an apartment.
a decent room in a shared apartment costs about 1100 - 15000 CHF per month. Obviously the more people sharing the cheaper the room but the above prices are based on 2 - 3 people in a flat. There are roms for less than 1000 CHF but in lower standard and crowded flats. For a large room in a nice central area you can pay up to 2500 CHF.
Take the advice mentioned above, anything less would be too good to be true ( aka scam - Craigslist and other portals especially requiring advance transfer of monies to a bank in a currency other than the CHF ).
She's either a very enthusiastic newbie or looking to up her post count to be able to use the market place. ( and the threads was resurrected by someone a couple of days ago)