College is a costly undertaking. The average annual budget for a college student at a public four-year institution in 2019-2020 was $26,590 vs. a whopping $53,980 for a student at a private, nonprofit four-year school, per the College Board. Ouch! Clearly, unless you're very well-off, you're going to have to be socking away a lot of money to cover your kids' college expenses. The stock market is a great wealth builder for your long-term dollars -- meaning money you won't need for at least five, if not 10, years -- and exchange-traded funds (ETFs) are a convenient way to load up on stocks. Image source: Getty Images. Here's a look at 18 ETFs with solid performance histories and promising futures. Sticking with stocks The simplest way to jump into the stock market is via a low-fee, broad-market index fund, such as one that tracks the S&P 500. Such a fund will aim to hold the same stocks in the same proportion in order to earn pretty much the same return (less fees, of course). The SPDR S&P 500 ETF is a great example, with an expense ratio (annual fee) of just 0.09%, meaning that it will lop off only $9 of a $10,000 investment each year. The S&P 500 index is made up of 500 big American companies, such as Apple, Johnson & Johnson, Walt Disney, Netflix, Costco, Bank of America, and Southwest Airlines. Over the past 10 years, the S&P 500 averaged 12.2% annual gains and an even higher average, 14.4%, with dividends reinvested. Promising ETFs for long-term growth You can aim to do even better than that, though, by parking some of your dollars in carefully chosen stocks, mutual funds, or ETFs that you think will outperform the market average. The table below offers a bunch of contenders for your consideration. It's long, but that's in order to give you a broad range of ETFs to choose from for a closer look. You'll see that many, for example, are focused on particular sectors or industries. Some, after all, are growing more briskly than others and are likely to continue doing so. You'll also see some focusing on certain kinds of companies, such as large companies, mid-cap companies, and growth companies. Most have expense ratios of 0.20% or less, which is quite low, and the rest are at 0.60% or considerably less. ETF Name Ticker 10-Year Avg. Annual Growth Rate Representative Holdings iShares U.S. Medical Devices ETF IHI 17.9% Medtronic, Intuitive Surgical Invesco QQQ Trust ETF QQQ 22.4% Apple, Amazon.com iShares S&P 500 Growth ETF IVW 16.4% Microsoft, Facebook iShares Russell 1000 Growth ETF IWF 17% Alphabet, Visa Vanguard Growth ETF VUG 18.5% Apple, Microsoft Vanguard Information Technology ETF VGT 20.3% Microsoft, Intel Vanguard Russell 1000 Growth ETF VONG 17.9% Amazon.com, Facebook Technology Select Sector SPDR Fund ETF XLK 19.7% Microsoft, Apple iShares PHLX Semiconductor ETF SOXX 21.5% Qualcomm, Broadcom SPDR S&P Biotech ETF XBI 20.9% Inovio Pharmaceuticals, Invitae Health Care Select Sector SPDR Fund XLV 15.5% UnitedHealth Group, Merck Consumer Discretionary Select Sector SPDR Fund XLY 17.6% Amazon.com, Home Depot Vanguard Total Stock Market ETF VTI 13.7% Microsoft, Apple Fidelity MSCI Information Technology Index ETF FTEC 20.8%* Visa, Microsoft Nuveen ESG Mid-Cap Growth ETF NUMG 17.7%** Splunk, Snap SPDR S&P Internet ETF XWEB 28.6% Overstock.com, Match Group Invesco DWA Healthcare Momentum ETF PTH 19.6% Novavax, Teladoc Health Source: Yahoo! Finance, fund websites.*Since inception, 10/21/13.**Since inception, 12/13/16.***Since inception, 6,27,16. Keep this caveat in mind, though: Past growth rates will not necessarily continue in the years to come. The next 10 years are not likely to be just like the past 10, so each of these funds is likely to sport a higher or lower average return. How should you choose? Think about which fields you think will grow fastest, perhaps doing some digging to gather information online. You might, for example, end up especially bullish on internet stocks and healthcare stocks. If so, perhaps park some money in one or more ETFs focused on those. If you've got a lot in large stocks, perhaps add an ETF focused on mid-cap or small companies. Note, too, that there can be a lot of overlap in many ETFs. Large-cap-focused ones, for example, are likely to have much of their assets in companies such as Apple, Microsoft, and Amazon. In some cases, they may have 20% to 40% or more of their assets in such companies. However you go about it, be sure that you're saving and investing for your kids' educational futures. There are many ways to do so, and some or many of the ETFs above are worth considering. At a minimum, consider just putting many or most of your long-term dollars in an S&P 500 index fund. 10 stocks we like better than WalmartWhen investing geniuses David and Tom Gardner have an investing tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Walmart wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks Stock Advisor returns as of 2/1/20John Mackey, CEO of Whole Foods Market, an Amazon subsidiary, is a member of The Motley Fool’s board of directors. Suzanne Frey, an executive at Alphabet, is a member of The Motley Fool’s board of directors. Teresa Kersten, an employee of LinkedIn, a Microsoft subsidiary, is a member of The Motley Fool’s board of directors. Randi Zuckerberg, a former director of market development and spokeswoman for Facebook and sister to its CEO, Mark Zuckerberg, is a member of The Motley Fool's board of directors. Selena Maranjian owns shares of Alphabet (A shares), Alphabet (C shares), Amazon, Apple, Costco Wholesale, Facebook, Inovio Pharmaceuticals, Intuitive Surgical, Johnson & Johnson, Medtronic, Microsoft, Netflix, Splunk, and Walt Disney. The Motley Fool owns shares of and recommends Alphabet (A shares), Alphabet (C shares), Amazon, Apple, Facebook, Home Depot, Intuitive Surgical, Invitae, Match Group, Inc., Microsoft, Netflix, Qualcomm, Splunk, Teladoc Health, Visa, and Walt Disney. The Motley Fool recommends Broadcom Ltd, Costco Wholesale, Intel, Johnson & Johnson, Southwest Airlines, and UnitedHealth Group and recommends the following options: long January 2021 $60 calls on Walt Disney, long January 2021 $85 calls on Microsoft, short January 2021 $115 calls on Microsoft, short January 2022 $1940 calls on Amazon, long January 2022 $1920 calls on Amazon, long January 2022 $580 calls on Intuitive Surgical, short January 2022 $600 calls on Intuitive Surgical, and short October 2020 $125 calls on Walt Disney. The Motley Fool has a disclosure policy.Source