Non-Ugly Interior Window Gates?

We’re looking at buying a street-level apt that’s currently w/o any security.  Just learned that we’re not allowed to install window gates on the building’s exterior (unfortunately).  Any recommendations on styles of interior gates that aren’t completely freaking ugly?  We need the type that can be easily opened by us when we want, to open windows or whatever.  ) I thinnk only that kind is legal, anyway.)  We’re not rich, so can’t afford custom gates.  Are there any prefab that are decent?  Info on where to buy, or a reliable installer?  I’d really appreciate any tips/leads.