Obviously you couldn't buy a real nuclear submarine from a comic book ad. You'd have enough trouble buying one if you were an entire country, with all the resources and wealth that afforded. In either case, you almost shouldn't have a nuclear sub, because they are dangerous and expensive and dangerous. The Polaris Nuclear Sub claimed to be over seven feet long big enough for two kids and promised the ability to fire rockets and torpedoes. For only $6.98? A steal for child or banana republic alike! Throw in a real periscope and light-up controls and you're sold. Cardboard, it was made of cardboard. You know what is neither watertight nor resistant to water in any way? Cardboard.
Tom Baker is the Comics Editor at WhatCulture! He's heard all the Doctor Who jokes, but not many about Randall and Hopkirk. He also blogs at http://communibearsilostate.wordpress.com/