It depends what you are investing in but, if it's equities and especially equity indices, one way that I know of (for those who have access) is spread betting. In the UK, you can effectively buy and sell futures with low spreads, and no taxes or commissions.
Today, for example, I can sell or buy the Dow at a price of 17320/17344 to settle in January 2016. On the site I use, I believe I need to have £50 of margin for each point I buy, so I can effectively buy a position of £173,000 by just having £500 deposited (though a very small movement against me will lead to having to put in more money or having my position closed).
If you can put in £1,750, you can have, say, a position of £173,000 which will stay open unless the index goes more than 1% below where it is now, or £86,500 open until it goes more than 2% below where it is now, etc.
The idea of buy-and-hold doesn't work well with the idea of leverage, since when you've got leverage you will always have the risk of being closed out, but you can increase the risk of your position by, say, 10 times and only be closed out with a 10% move against you.
I'm not a financial advisor and nothing I write should be considered advice of any sort.