Greetings,
Most Swiss banks offer rental deposit accounts - a form of blocked account which can only be accessed under certain conditions (when you move out or fail to pay your rent, for example).
If you do not have money to put down a deposit, you have two other options:
1. Take out a personal loan. Make sure to get the cheapest loan available. You can compare loans using the moneyland.ch personal loan comparison. The exact interest rate you get depends on your creditworthiness.
2. Take out rental deposit insurance. You pay regular premiums for this insurance, which in turn provides your landlord with a guarantee against your defaulting on your rent. You can compare rental deposit insurance using the moneyland.ch rental deposit insurance comparison.
Whether a personal loan or rental deposit insurance works out cheaper for you depends on your creditworthiness - among other factors. In both cases you should compare offers and use the cheapest available option which matches your needs. You can find more information in the article: Loan or rental deposit insurance?
Best regards from Moneyguru