Open Source Software for Business — yes, you guessed it — big business.

According to Gartner, businesses will likely spend $503 billion on enterprise software in 2020, 10.5 percent more than last year. With business application expenses taking an ever-larger share of their IT budgets, many organizations are looking for ways to cut costs, and that leads many to consider open source software. In fact, a survey conducted by Black Duck Software found that 65 percent of companies were increasing their use of open source software in 2020.

Thanks to their lower licensing costs, many open source applications offer lower total cost of ownership than similar proprietary software. Open source business software also offers other benefits, such as the ability to customize the source code to meet a company’s exact needs. In addition, many of the best open source applications offer features that can’t be duplicated by closed source applications, and some feel that open source offers better security because of the number of people involved in writing and revising the code. Open source also helps organizations avoid vendor lock-in.

The open source community has created literally hundreds of applications for business users, and as with proprietary software, the quality of this software can vary greatly. For this slideshow, we’ve selected twelve of the most popular and well-known open source applications for businesses. They come from a variety of categories, including enterprise resource planning (ERP), customer relationship management (CRM), project management (PM), business intelligence (BI) and business server software. Many of the organizations behind these projects also offer paid support and services for organizations that would like to purchase them.