Whichever company you chose check the insurance cover. With Patrick location I found that I could not bring the insurance liability down to below 750 or 1000 francs so that is the vehicle was damaged even while i was not in it, I would be liable for the first 750 or 1000 francs.
The cheapest rates are on the car hire websites eg easycar carrentals etc but that does not help you with the insurance problem.
To bring your liability down to zero doubles the initial cost of car hire
In a recent hire from Budget (in England) I found that it ws only 15 francs per day to bring the liability down to 150 francs - could not bring it down to zero. And of course i had a puncture (my first one in years) and so will probably have to pay for the new tyre.
It is a question of maths and risk. The only way to find the cost of the extra insurance is to phone the car hire company before you commit yourself on the website.
In Switzerland I use a combination of mobility and train. Alternatively you can get anywhere by public transport or public transport and mountain taxi and it is only worth hiring if you are several people