What exactly is changing with Chaos?

Yup.
That's why books are so expensive in kMS.

Of course all our dirt cheap books will rise in price. Any book with a huge arse supply before chaos will take a hit from this and grow more expensive, but the rare books not dropped at the common training grounds or at HT will eventually be cheaper. I have no idea about KMS market, but their economy is not similar enough to ours to base certainties on. But I guess this will not matter in the end anyway. Hacker scum run our economy, the books will be priced according to what they feel like getting/paying.