I have a Liberty safe and really like it . An alternative is a Knaack tool storage box model 4824 .
http://www.knaack.com/index.htm
I used one of these for years until I broke down and got a safe . They run about $260 for a 48"x23"x24" box , the box uses 2 padlocks for the locking system and they are both mounted inside the box with only the key hole visible . They are a lay down type so you will need a little extra floor space . They are vastly superior to the Homak style gun cabinets and you would need a torch or saw to break into one . We use them on construction sites and I have seen them hit by cars and they did not open . Later when you buy a safe you can use them for ammo storage . Good luck , Mike...