Mine was $40 at a Wal-mart sale (MSRP is $50). It's a Winchester WM-180-7 electronic pistol safe. It came with a small piece of felt padding, but I use an old wadded up t-shirt, instead. It requires both a key and a code punched on the keypad to unluck it, but if the battery fails, a separate and different key I keep locked up elsewhere is used instead of the keypad.
It's not fireproof, but it does have mounting holes in the back for wall-mounting and securing it against casual theft. If you built a wooden mini-rack, you could probably fit five or six normal-sized semi-autos. It's big enough for a Ruger Redhawk, too (.44 mag, 7-1/2" barrel).
For twice the capacity of "12 long guns and 8 handguns," though, you're looking at a much larger safe. Costs vary widely. I've seen some real cheapies large enough for $500, but I've also seen ones of similar size but of much better quality and features for upwards of $3,000.
Out of my league!