Avoid Bookshop.org. They claim that "every purchase supports local bookstores" but their website is pure evil woke NWO. Their logarithm is hilarious, though. Searching for St. Thomas Aquinas brings up suggestions for medieval Yiddish folklore, while searching for St. Alphonsus Liguori brings up suggestions for basic vanilla self-help affirmations and woo-woo new age rubbish.
Alibris.com is very good for range of offerings and low price, and you'll know exactly which local bookstore is the source of whatever you buy.