Below are two pictures of my gun safe. It's a Sentry S2210 that I bought at Wal-Mart for $300. It weighs 200 lbs. and holds 8-12 guns. To fit it in without removing the ammo shelf, I had to put my shotgun in the very front.

Wal-Mart also sells the FS2920, which holds more guns, is fire-resistant, and has a combination lock instead of the 4-bit key on this one. It costs $400, weighs 300 lbs, and wasn't in stock at my local Wal-Mart, so I got this one. It's four inches higher, so I think the shotgun would fit under the shelf.

The links above are to deansafe.com, which will ship you one of these safes or a number of others. They charge about the same price as Wal-Mart, but you also have to pay shipping.

Click on either image for a higher-res version.