Among the criteria I consider when selecting funds for the Fool's Champion Funds investing service, market-beating performance and plenty of managerial experience rank near the top of my list. Those are typically two of the key ingredients that go into the best and brightest the mutual fund industry has to offer.

As important as those attributes are on their own, even together, they're not enough. In addition to the right performance and a well-seasoned manager, I need to see a reasonable expense ratio. As my wife will be only too happy to tell you, I am a dyed-in-the-wool cheapskate. I'm just not willing to pay through the nose (or any other body part, for that matter) for a mutual fund.

The price you pay
Actually, my miserly ways aren't my only motivation to focus on a fund's price tag. When you're trying to get a bead on a fund's future prospects, few attributes are more telling than the expense ratio. This only stands to reason. A high price tag puts a fund at a distinct disadvantage, giving the fund's manager more ground to make up each year just to stay competitive with cheaper rivals -- not to mention his expense-free benchmark. Conversely, a reasonable price tag gives a fund a head start, fattening the bottom line (i.e., your return) year after year.

But what, exactly, is a fair price to pay for a mutual fund? Good question. On some level, expenses are relative. All things being equal, if the typical stock fund's expense ratio will ding you about 1.5% per year -- and it will -- anything less is reasonable, at least comparatively speaking. On the other hand, all things aren't equal. And with alluringly cheap index options such as Vanguard 500 (VFINX) there for the taking, a fund generally needs to be a good deal cheaper than the average to get my attention. Indeed, I'm a big fan of expense ratios that fall below 1%. Sure, that's an arbitrary number, but at least it's arbitrarily low.

Exceptions to the rule
That said, I am willing to consider pricier fare. If a terrific manager opens a new fund and, owing to its initially small asset base, that fund costs a little more than I'm used to paying, I'll still give it a look. As the fund grows in size, though, I'll certainly expect to see its expenses come down. If you own a fund whose asset base has ballooned while its expense ratio has stayed high, you might consider selling. Economies of scale should make things cheaper, and with more dollars available from which to deduct fees, the hit each individual investor takes (in the form of the expense ratio) ought to decrease as a fund's asset base grows.

A performance-based management fee is another reason I'll consider paying up for a fund. I'm a big fan of the way such fees align the interests of managers with those of their shareholders. Indeed, I like that aspect of them so much that I -- penny-pincher that I am -- once wrote favorably in Champion Funds about a fund with a price tag of 1.9%. In fact, that figure looks positively cheap relative to the margin by which the fund has outperformed the S&P 500 since its inception, but make no mistake: As its margin of outperformance has ebbed, so has the price tag, which now weighs in at a comparatively thrifty 1.15%.

C'mon, you just gotta love that.

Exceptions that prove the rule
On the other hand, sometimes a fund that looks cheap really isn't. Consider the case of Fidelity Magellan (FMAGX), which is currently closed to new investors. At just 0.59%, you might think this celebrity fund is going for a song, but for a good many years, the fund that Peter Lynch made famous was basically a closet S&P 500 tracker.

Fidelity has taken steps to right this situation by bringing in a talented new manager, but the jury is still out on how he'll fare given Magellan's massive asset base. The historical record, however, is clear. At the close of September 2005, Magellan's portfolio looked like the VIP section at a blue-chip party: American International Group (NYSE:AIG), General Electric (NYSE:GE), American Express (NYSE:AXP), and Wal-Mart (NYSE:WMT) were all among its holdings. ConocoPhillips (NYSE:COP), Wells Fargo (NYSE:WFC), and IBM (NYSE:IBM) made the portfolio's upper-crust guest list, too.

Why pay a premium for that, particularly when Fidelity's own S&P tracker, Spartan 500 (FSMKX), and the SPDRs (SPY) exchange-traded fund (ETF) are available for just 0.10%?

The bottom line
Fund expenses are more than just the price you pay to invest. When you get right down to it, they're a part of the fund itself, a feature of the product you're buying. How could it be otherwise? Expenses have a direct impact on the fund's relative and absolute performance, and simply put, to the extent that they're lower, your fund is likely to do better.

It's also more likely to make the grade as a Champ. To be sure, no single attribute -- price tag included -- is sufficient to secure that status. But if I had to choose only one data point to consider before judging whether a fund is likely to beat the market over time, the expense ratio is the first place I'd look. And if you'd like to see the market-beating funds I've dug up, click here to grab a Champion Funds free pass.

This article was originally published on April 20, 2004. It has been updated.

Shannon Zimmerman, Motley Fool Champion Funds analyst, knows when to hold 'em -- and when to fold 'em. He doesn't own any of the securities mentioned. Wal-Mart is an Inside Value selection. The Motley Fool is investors writingfor investors.