Main parking in centre, approx 2€ per day and safe https://goo.gl/maps/f3ocUojptFtzU7PK7
Another option near "Turistická chata" https://goo.gl/maps/RiugwTMPNVr5aPKo9
Don't ever leave car "U křížku" https://goo.gl/maps/bfjbLG9C8G7CPXch9. That's nr#1 car break-in place.