The problem with using Perseus and all the other free online Greek and Latin texts is that you wouldn't have commentary and suitable glossary. Unless your Greek and Latin are amazingly good, you NEED commentary and glossary. Even the Loeb Classical Library is deemed inadequate for learners because of this. You want something like these:
Cambridge Greek & Latin Classics - Cambridge University Press
and books like those aren't usually sold in bookstores. Most libraries don't have them too, because they are more like textbooks than reference/research books. To get them, your best way would be to order them online or to buy them from campus bookstores when a professor assigns them for a course.