For what it is worth, I think he mentioned many of these authors because you can find them FOR FREE. Yes, you can find the Summa Theologica in a couple of different translations if you look diligently on-line. Archive.org is a brilliant and valuable resource. Ditto Orgien and many of the Church Fathers are available for ebook, which can also be read on a computer. There are many authors that I could not find for a reasonable price any other way. Another way to find them is on Amazon or Google—but be careful, it can be hard in Google books system to tell the difference between copyrighted and non-copyright books in their collections.
IF that is not possible, then you can go to Archive.org’s audio files, and you can download—for example, “The City of God” by Augustine for free in it’s entirety and it is one of the nicest recordings they have. I want to see if anyone was brave enough to read the Summa, because I find that the much older theologians are much easier to understand when you listen to them, rather than read. I’m not sure why—Augustine was entirely opaque to me until I listened to “The City of God’ and it was almost like listening to him explaining things to you.
Check out libra vox, not all the recordings are this excellent, but the more… theoretical works tend to have quality adherents.
The hardest thing about Aquinas is that he begins from the very beginning, and uses words that mean different, sloppier things to the modern ear. Philosophy majors still use those words correctly, but there is a certain learning curve, but if you go to the “Aquinas Online” site, there are articles written for beginners that explain patiently without all the philosophical nonsense that you might get on University websites. Below are a few links…
Also, the Catholic Encyclopedia is also on line. Just about everything I have ever read either makes more sense, because of Aquinas. So much of the modern nonsense wouldn’t stand for two seconds if we still knew him and his basics.
And it doesn’t cost a thing… except time. Which I think is the real barrier.