What stopper will stop HCl fumes?
it smells bad, and the beer bottle's metallic label is slowly corroding.


That's, unfortunately, very common. At one of my former labs 'acid' cabinet  was corroded from within. For this reason it is recommended to keep such bottles under fume hood.

AFAIK, common stoppers are made from polyethylene or polypropylene. At one of my former labs concentrated hydrochloric acid was stored in stock plastic canister, similar to that used to store petrol (on the other hand, both nitric and sulfuric acids were stored in 20l glass bottles, even though the stoppers were made from same polymer).  I HIGHLY recommend to by (or order by mail) dedicated chemical bottles with caps, though. They are usually fairly cheap and pretty universal.