Lowes sells a 7-14 gun safe that can be configured for half long guns and the other side selves for pistols or gear, has a locking ammo locker on the inside and a little shelf, with some elastic rope on the door. I wouldn't consider it a SAFE although it is sold that way, it's more of a storage locker. They run about $427, it won't stop a thief, but it will slow them down, and prevent anykind of smash and grab type of events. Think they weigh close to 400lbs, so you'll need a refridgerator dolly. A roll of X-Mas paper will camo your new purchase while you move it in, no need to show the neghbors you have so many weapons that you need a safe.
Another option, is a tall sentry fire proof safe, I think they sell a 2.2cu model that should hold several hand guns and a complete lower reciever, they're around $200 and weigh in around 200lbs, plus they're fire proof. Down side is a single man or 2 men could carry it out.
Several years ago, I drilled and 'liquid nailed' 1ft long 2" eye-lets into the floor and ran a titanium bike cable through them and the locks of my pelican case, kind of a gheto set up but better than nothing. I've seen people hang thier guns inside of suits and over coats to hide thier location. If you have the furnace and water heater in your apartment this maybe a good location as well.
Cost-Co and Sams Club also sell safes, for around $650.
If you live on the ground floor of an apartment, just go ahead and drill it into the floor, make sure you use a vacumee while you drill, the holes aren't that noticable, till the carpet is pulled up and then just play dumb. There's alot of people that buy cheap safes or have no safe... I used to say that my safe was cheaper than my cheapest gun, my safe was still cheaper than my cheapest shotgun
Let me see someone walk off with a 700lb safe. Down side is that there's been a few posts that people were ambushed in thier homes after a burglary, when the bad guys saw the safe them came back armed to have the owner open it.