Investing - Funds: People love to buy things on the cheap, which is why it's puzzling that more investors don't consider expenses. You can find some real bargains among funds. In fact, comparison-pricing your mutual funds --and dumping the expensive ones -- is one of the best investment moves you can make.Mutual funds charge shareholders for expenses: management fees, advertising, rent. These expenses are expressed as a percentage of the fund's assets, called the expense ratio. The average stock fund charges about 1.5% of assets each year.

You may not notice the expense ratio. When you look at your account balances, expenses have already been taken out. But your expenses can be a tidy sum. Suppose you have $50,000 in your account. If the fund goes nowhere all year, you've simply paid $750 to the fund management. That's not chump change.

Your real expenses could run much higher. A fund's trading costs aren't part of the expense ratio. As a rough rule of thumb, you can tack on about 1/2 to 1 percentage point to the expense ratio for trading costs -- more, if the fund trades frequently. The expense ratio also doesn't include upfront sales charges, or loads, which you pay if you go through a broker to buy the fund. More on those in a moment. But if the average fund is charging 1.5% a year for expenses and racking up 1% more in trading costs, you're paying $1,250 a year on a $50,000 account. Shaving those costs might save you more than you think.

Let's consider two funds. BigExpensiveFund charges 1.5% a year in expenses. LessExpensiveFund charges 1%. You invest $50,000 in each. We'll assume you earn 7% a year in each fund.

Let's see how the two funds compare. We'll use the SEC's mutual fund expense analyzer, the latest version of which is at www.sec.gov. After 10 years, BigExpensiveFund has cost you $13,797 in fees and forgone earnings on those fees. LessExpensiveFund: $9,405. That's a $4,392 savings. You could buy a lot of toasters with that.

The savings can be even more dramatic in a bond or money market fund. The average money fund yields 3.63%. If you pay 1% in annual fees, you're giving back more than 20% of your yield to the fund company.

Finding a fund with low costs isn't just a cost-cutting step. Though there's no way to guarantee fund performance, it's a good bet that a decently run fund with lower expenses will outperform a similar higher-cost one over time.

Suppose you decided to buy a U.S. government bond fund 10 years ago and that your sole criterion was the fund's expenses. You divided the entire group of bond funds into four groups. Group 1, which we'll call the Horribly Expensive Group, had the highest expense ratios. Group 4, the Smart and Thrifty Group, had the lowest.

The Horribly Expensive Group gained an average 54% over the past 10 years, or about 4.4% annually. The Smart and Thrifty Group, though, gained an average 69%. That's not to say there weren't stinkers in both groups. On average, though, the lower-cost funds performed better, because expenses didn't take as big of a bite out of returns.

You can find most funds' expense ratios at www.usatoday.com/money (click on "fund screener") or by reading the prospectus. If you're looking for low-cost funds, consider:

Index funds. Not all index funds have low expenses, but most do. The Vanguard 500 Index fund charges just $18 a year on a $10,000 investment, which is cheaper than a barrel of mice. Index funds simply track an index, such as the Standard & Poor's 500-stock index.

But you can find an index fund that tracks nearly anything these days, from the S&P 500 to the Israeli stock market.

Big funds. It doesn't take 10 times as much money to run a $1 billion fund as it does to run a $100 million fund. Most fund companies with a bit of conscience reduce fees as a fund gets larger.

No-load funds. The average no-load stock fund has a 1.23% expense ratio, vs. 1.40% for the average broker-sold fund that charges an upfront commission, or load. One reason: Many broker-sold funds have added 12b-1 fees, which go toward advertising or paying a broker.

If you invest through a broker, you'll find a dizzying array of fund share classes for each fund. Each class has a different expense ratio. The share classes typically represent different ways of paying your broker. Nothing wrong with that.

But you still have to figure out the best deal for you. Long-term, buy-and-hold investors are better off with a fund's A shares, which have the lowest ongoing fees but the highest upfront commissions.

You can save even more by asking about discounts for larger investments. The Growth Fund of America's commission falls to 5% from 5.75% if you invest $25,000.

You can hit those lower commission levels, called breakpoints, if you or your family has money invested in the same fund family ? or even if you pledge to invest more money in the next 13 months. The NASD has an online tool that can help you get lower commissions: www.nasd.com.

Shopping for a low-cost fund isn't always easy or fun, but it's a great way to boost your returns. Think of the savings. Think of the gains. Think of the toasters.

John Waggoner is a personal finance columnist for USA TODAY

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