Here's a video of Holland & Holland's craftsmanship in display.
The price? You can't afford it if you have to ask. One of the firearms is listed as £635,000 - about $1 million USD. Cheapest one is £10500, about $16,800 USD (from London Gun Room)
Land Rover is coming out with 120 Range Rover Holland & Holland editions. It is priced at £180,000(about $280,000).