I used to work in a company that allowed me to put up to 9% of my before-tax income in a 401K. They would then match the first 4% of that income, so I was saving (and sheltering from the tax man!) an astonishing 13% of my income. Since I had a very good paying job, I was able to fully take advantage of this program. The company, no doubt. got all sorts of tax breaks for setting up the program.

But wait, there's more!

I could borrow money from my own 401K if I wanted to buy a big ticket item, such as a house, or car (or boat!). And I could pay myself back (with interest). This meant I had an interest-free loan, from myself, that cost me absolutely nothing. The only cost to me was that money I borrowed from myself was not accumulating at the 9% compound interest the 401K plan was paying me, but it was still possible in this way to increase your real income substantially while reducing your tax bracket.

And then, to top it all off, that interest I paid my own 401K along with my loan repayment...was deductible from my income so I could lower my taxes even more.

The only catch was that in order to play this game, you had to be affluent enough to be able to live on 91% of your paycheck. This kept out the riff-raff.