This post originally appeared at 24/7 Wall St.

Just because certain products have a low price tag does not mean they cannot sell for billions of dollars. In fact, some of the cheapest products make the most money for their companies.

24/7 Wall St. identified some of the best-selling consumer goods and food products costing under $5 and the companies that make them. The cheapest and most successful products are sold by companies with the strongest and oldest brands that spend the most on advertising.

All of the companies that make the most money from selling inexpensive items have exceptionally strong brands. They are highly recognizable and held in high regard. Coca-Cola, which makes billions of dollars off its trademark drink Coke, is the most valuable brand in the world, according to brand valuation company Interbrand.

According to Brand Z, McDonald’s, producer of the world’s favorite french fries, is the most valuable brand. Other brands, such as Cheerios, Campbell’s, and Starbucks, are also instantly recognizable.

These products have such strong brands partly because their parent companies spend huge sums of money on advertising. In 2011, Procter & Gamble, maker of Gillette razors, spent $9.3 billion on ads for all products — 11.3% of its total sales.

This amount increases substantially each year, reflecting the lengths companies must go to preserve market share. Ian Cook, chief executive of Colgate-Palmolive, recently promised “increased advertising support behind many new and existing Colgate products” in 2012 to protect its global standing. The company said it had increased advertising spending in the fourth quarter to $428 million, up 5% from one year ago.

Additionally, these brands benefit from having been around for years and having existed in the public conscious a very long time. Products such as Coke, Colgate toothpaste, and Dole bananas have been around since the 19th century. Campbell’s soup and Cheerios have been household staples since the middle of the 20th century. Consumers have grown to trust the brands and expect a certain level of quality.

24/7 Wall St. reviewed the 500 largest companies by sales to identify the ones that focus on inexpensive consumer goods and low-priced food products. We then looked at the most inexpensive products sold for less than $5 and hold the highest market share. These are the cheapest products making American companies billions.