If I had $100,000 handy, I would bid for theSea Shadow, the stealth ship that DARPA built for the US Navy in 1983. It's now for sale at GSA Auctions. The original price tag: the US Government paid $195 million to Lockheed Martin to build it. And you get a HMB-1 Mining Barge too in the package too.
Needless to say, this ship would be perfect is you want to be a superhero or a supervillain.
The price will keep going up, for sure. It started at $50,000. But it will not get anywhere its original price tag. The reason: the US Government doesn't want you to keep it in its original form. If you want to buy it, you will have to destroy it! It has to be converted into scrap. More here.