The PostFinance
Online Set sounds like a good option for you. 3 CHF / month or free if you keep at least 7,500CHF (or the equivalent in EUR) of assets in total in aggregate in your accounts. They also offer the
Plus Set with some additional advantages (free withdrawals abroad and branch transactions) for 12 CHF / month, or free with a minimum of 25,000 CHF of assets.
You can have both a CHF and a EUR account (at no additional charge) in the same set at PostFinance, so there's no need to choose.
Living here I suppose you'll need CHF in your day-day life. If you are paid in EUR, I'd guess you can either get paid into the CHF account and have the payments exchanged by PostFinance (at their EUR buy rate) on receipt, or get paid into the EUR account with no exchange overhead, and then exchange as much as you want (at the same rate) by transferring within the set to your CHF account whenever you need more local money. Notwithstanding potential fluctuations of either currency's value, the latter is probably more efficient if you occasionally need EUR, as you avoid having to buy them in exchange for CHF which you got for EUR in the first place; and you get a higher interest on your balance, of course.
May this be the most difficult choice you'll have to make in the near future
Cheers,
-- Tom