Many believe that investing is only for people with a lot of money, but that couldn't be further from the truth. Investors can find quality stocks at almost any price point if they know what to look for.

For example, the three companies we are going to focus on today each offer stock trading at under $20 per share, are among the leaders at what they do, and have long-term growth opportunities. You can own a piece of each of these businesses for the cost of a dinner at your favorite restaurant. Roll up your sleeves and dive in.

1. AT&T: A leading telecom giant

AT&T (T -1.19%) is a telecom company that operates the largest wireless network in the United States. Consumers have come to rely so much on their smartphones that they will prioritize paying their smartphone bills right up there with buying groceries and putting gas in their cars, making AT&T a utility-like stock in terms of revenue generation and one that investors can depend on.

Granted, the stock itself probably won't make you rich. Revenue has grown an average of just 2% annually over the past decade. However, the company pays a massive dividend that is yielding 7.5% at the moment. That makes it an excellent stock for producing passive income.

Wireless networks are becoming increasingly important to technology; 5G network speeds make new applications like the Internet of Things (IoT), autonomous driving, and streaming more practical. AT&T's role as the country's largest telecom network all but ensures that AT&T will be there to participate in these opportunities.

2. Ford Motor: An old car company learning new tricks

The Ford Motor Company (F -1.57%) has a legacy of building cars that goes back more than a century. Building cars is a tricky business; it's very competitive, and car companies spend billions paying for factories, labor, and the development of new technology. Yet Ford has stood the test of time; its F-series pickup trucks are the top-selling vehicles in America.

Momentum for electric vehicles has picked up in recent years, led by the emergence of Tesla as a major player in the automotive space. Some existing car companies could struggle if they can't adapt to consumers' electric vehicle demand, but Ford seems to be doing well at that.

The company has already brought electrified versions of its three most popular models to the market, including the Mustang (Mach-E), F-Series (F150 Lightning), and Transit Van (E-Transit). Ford has plans to increase its electric vehicle capacity to 600,000 units annually by late next year. Ford could remain a fixture in the automotive industry if it can grow its capacity to keep up with customer demand.

3. Opendoor: Changing the way you buy a home

A more speculative investment, Opendoor Technologies (OPEN 6.27%) is reinventing how people buy homes. The company buys houses with cash offers and resells them on the open market, a practice called iBuying. But this is not a home-flipping business; Opendoor uses technology to make the experience feel more like an e-commerce transaction than a painstaking process that traditionally lasts weeks and involves many parties.

Opendoor makes money by charging a transaction fee and focuses on buying and selling as many homes as possible, not on trying to buy and sell for a profit. The company's operating margins are meager because of this, and Opendoor is trying to prove its business can endure both the ups and downs of a fluctuating housing market.

Opendoor is a far more speculative stock than the other two companies on this list, but the potential upside is far more significant. The collective value of residential homes in the United States is more than $43 trillion, and 6 million to 7 million homes change hands yearly. The long-term opportunity is massive, and Opendoor's new partnership with former competitor Zillow could help take its business to that next growth phase.