Say you are single, have some experience and get low-balled into a CHF 100k contract. Not counting 13th salary this translates to CHF 7.7k per month gross / CHF 6k net (before health insurance). I.e. at up to 1/3 of your monthly net you can spend up to 2k per month on an apartment. There are plenty of those to choose from inside Zurich city, even if some might be small for the price or have other drawbacks. You can find cheaper/bigger/nicer easily by expanding your search radius to the (extremely well-connected) suburbs.