Scholars such as myself, who operate in the bush leagues, in universities where library funds are spent on items students will actually use, are probably just SOL when it comes to certain prohibitively expensive books.
Take for example, volumes in the Corpus Christianorum Series Apocryphorum, which present contemporary, authoritative critical texts of the Christian apocrypha. If I want to study the Ascensio Isaiae and write about it with any authority, I require access to the two-volume CCSA edition of the text and commentary on it. But my library doesn’t have these books, and neither I nor anyone I know owns them.
So, what to do about it?
I might be able to acquire the volumes temporarily via ILL, but won’t have them for long enough to do all the work I might do.
Or I suppose I can visit a research library that holds them, and consult them there, but then the same problem obtains. Soon enough you have to make that four hour drive back home. These books are designed to be reference works used on an instance by instance basis.
(I shouldn’t even mention the complication that the scholarly contributions to this edition and commentary—excluding the Ethiopic, Coptic, Greek, Latin, and Slavonic texts—are in Italian.)
What I can’t do is justify spending my own money on such books; that might amount to choosing arcane research over feeding and clothing my family. I’m a scholar, but I’m not crazy.
On ABE Books, the two volumes cost about $370, before taxes, shipping, etc.!
Perhaps it makes things better (or worse, depending on your point of view) to observe that the apparent function of advanced critical editions (especially in the CCSA) is not so much to enable scholarship, but to complicate it, control it, and limit it. They didn’t make these books to make anyone’s job any easier. The best hope for any producer of a new critical text edition and commentary is that they have published something that becomes an “indispensible tool” for future research (here I borrow the words of A. Hilhorst, regarding this volume, from his review in Vigiliae Christianae 54:1  111-114).
Being indispensible is good, if you can manage it. It guarantees that your labors will not be in vain, even if, as Hilhorst rightly complains, “the price of the volumes… will force the average scholar, like the merchant of pearls in the Gospel, to sell everything he owns in order to buy them” (Hilhorst, 2000: 114).
If you’re curious (or for some reason want to buy these books for me), check out the following:
Bettiolo, Kossova, Leonardi, Norelli, Peronne, eds., Ascensio Isaiae: Textus (Corpus Christianorum Series Apocryphorum 7). Turnhout, 1995. 444 p. ABE Books price: $162.30 Ascensio Isaiae: Textus.
Enrico Norelli, Ascensio Isaiae. Commentarius (Corpus Christianorum Series Apocryphorum 8). Turnhout, 1995. 722 p. ABE Price: $202.21
Ascensio Isaiae: Commentarius.