OP, my twins are 7 and I don't know that we've every spent $200 in one shot on books. And we have probably 500 books for them in the house (after having sold a ton at consignment sales). As people mentioned, thrift stores, consignment sales are great. Also there are used book stores in most major cities. Also most public libraries have a cart somewhere near the front door or checkout desk that have books that the library is getting rid of that you can buy at a discount. Last, I shop at places like
https://www.betterworldbooks.com/. They sell new books at a discount and used books. They collect used books at universities and libraries throughout the US. But an important part of the company is that a portion of every book sale goes to charitable literacy support, either supporting local reading programs, donations to public libraries and simiar projects.
$200 is way overboard in brand new books for an as-yet-unborn. As another PP pointed out, at this point, the words don't matter. An unborn infant cannot process words. What they process are the tones of your voice, and the emotions that you are are conveying. This is why people often play music to unborn fetuses. You can and should read, but what matters most is your emotional state and how you convey what you are reading, so it is true that you can read anything to your child and it will feel your love.