Open Access refers to information that is freely available through the internet with very few copyright restrictions. This designation is chosen by the author or copyright holder or is available through public domain.
Subscription journals recoup the cost of publishing from those who subscribe to the journals.Unfortunately, the costs associated with subscription scholarly journals frequently total thousands of dollars annually per title. And while those costs increase each year, library budgets are shrinking. The result is that fewer researchers can afford to access valuable information.
The open access model makes information freely available to end users. Although OA costs less than standard subscription publishing, there are still costs involved. OA costs are often paid by the author or their affiliated institution in the form of an article processing charge (APC).
Journals should post the possible charges clearly and accurately.
This blog explains the process in more detail:
There are organizations and institutions that will help OA authors pay APCs
