I think she said she'd trick the publishers to give her free books.
If need be, I hereby propose a modest "AWAD latin-scholarship fund". Since the teacher is donating (her time), why shouldn't we?

PS to JTD: Speaking as a father of college age kids (and presuming you're a bit younger than they). If your dad gives you grief about the excess volume of books,
(1) dump other books of equal of greater volume, and tell him so (gambit: if you don't want to dump them permanently, someone -- your teacher? -- will store them for you)
(2) point out to him that when you appy to college, it will look great on your essay to be able to say that you had the initiative to teach yourself latin; it could well translate into signifiant scholarship funds for college (especially since it will also earn you a sterling recommendation-letter from the spanish teacher). A superb investment.