I have been using Zotero for saving my references which is under a general public license so there is no cost to use it. There are a couple of great features it has. For one, it can be web accessible for the actual citation but then I can store attachments locally. Storing attachments locally is great since I can store the article pdf and also my notes with it (e.g. class summary papers I wrote on the article). Second, I can just enter the ISSN, ISBN or DOI of the article or book and it will enter all the bibliographic information. Finally, it will export to BibTeX so I don’t have to enter APA article information in my papers (i.e. that is done automatically).