There are many ways to access primary sources, it depends a lot on what topic you are interested in though. Many historical books which were significant are still published and are important sources (for instance Bernal Diaz's account of the conquest of Mexico or Cicero's speeches), also many private accounts, diaries, letters and so on which have become particularly famous are also published and easily accessible (the letters of Christopher Columbus giving an account of his voyages are published for instance, or the diaries of Samuel Peyps). Lots of famous and particularly important historical books are accessible for free online. There are also lots of edited compilations of sources which include plenty of unpublished material which you might find interesting. A good example is this book which is a collection of important primary sources on the history of modern China http://books.wwnorton.com/books/webad.aspx?id=4294974470. There are other similar books focusing on many other countries and periods. These books are quite expensive though and hard to get hold of if you don't have access to a university library. Plenty of sources are digitized and collected in online history sourcebooks though. For example here is a link to a very large online sourcebook at Fordham University https://sourcebooks.fordham.edu/mod/modsbook.asp This is a very good online archive on Soviet History (again I don't know what topic you're into but if you like Soviet history its very good and accessible) http://soviethistory.msu.edu/ Anyway loads of options for you! Hope you find some you like.