Or maybe, they want out of the EU, but retain the level of funding they get (which should result in lower costs for the UK government, which was a net payer to the EU)?!

But Leave promised all of that money to the NHS. Were they lying when they did so?

http://imgur.com/indvx6a

The UK is only a net payer if you discount the benefits of being in the largest free trade area in the world.

What's the magic formula they came up with where every single member is receiving precisely the same cost/benefits, and no one is getting even the slightest free ride?

Free trade isn't a zero-sum game.

Indeed it isn't, but it's also no guarantee of success, especially not to a level that magically matches some arbitrary corresponding cost.

The EU funding in Cornwall was largely wasted. It has been studied by auditors.

Most funding from most sources is largely wasted. That doesn't mean that the money won't be sorely missed.