Article Processing Charges (APCs)/Book processing charges (BPCs) are publication fees charged to authors - but often covered by their institution or funder - to make publications immediately open access, and should not be confused with other costs such as page charges or colour print fees. APCs can vary widely, however many Open Access journals do not charge these author fees. So you can avoid APCs and still make your work open access by publishing in such a journal, or by providing open access through self-archiving.
You can find an overview of trusted open access journals in the Directory of Open Access Journals.