A gun safe is for storing, a case is for transporting. A cheap gun safe that is simply bolted to the wall studs is very secure from burglary because one must open the safe to get to the bolt heads. A good lock (tumbler dial, not an electronic lock) is what is needed. The safe might go in a closet out of sight. These are not expensive if you check your local chainstore sporting goods shop regularly for a bargain. The expensive ones are fireproof which I avoided for economy sake.
A cheap large silica gel box can be recharged in the oven every few months, and will prevent rust. We're we're talking about a $5-$10 item that will last decades. The safe will last a lifetime.