At that price range, you can find a long-gun safe that holds about 10-12 firearms and has a decent fire rating. But if you're looking for a safe that can withstand a true 60-90 minutes of heat, sized for 10-15 rifles and equipped with a mechanical or dial lock, you're usually looking at spending over $1200...
So, it seems that the budget friendly lockable storage containers only come with electronic locks now. American Security still offers dial locks, and should have what youre looking for for just over what your budget is.