A fully-supported ERP system for just $500 per month? That's right, said OpenMFG CEO Ned Lilly, calling from Norfolk, Virginia. (Your mileage will vary, and OpenMFG has a calculator on its site to help you with that.)
Driving down the price of fully-supported software systems is an expected benefit from open source.
Here is an unexpected benefit.
"We’ve done some work integrating Mantis bug tracker records into Drupal. We contributed that back to Drupal. We also came up with a new module to make downloading easier."
There may be more contributions to come. "We're heavy users of PostgreSQL," Lilly said. "That’s our foundation technology. We haven’t contributed huge amounts of code back to it. But we’re still well known as serious users." But that, too, is a benefit to the community, because expert, active users build the project's knowledge base.
This is one of the hidden benefits of open source. Open source businesses use tools, make improvements, donate those improvements back and deliver value for completely unrelated projects. It's yet-another thing the proprietary world does not allow, another dimension in which open source is growing.