It's been 13 months since I last spent any money on a book, but this year's challenge will probably necessitate breaking that streak. I've got nine books unavailable from my library without an interlibrary request on my potential reading list for my sub-challenges right now.
So far I've requested two of them. The library is working on one and is actually going to add the other one to their collection. I don't have enough free time to read them all if they all show up at the same time.
My GoodReads shelf for to-read purchased items is down to 8 titles.