A big batch of "For Dummies" titles, mostly science or math, are part of the Kindle US Daily Deal today at $3.99.
This link pulls them up, but may also have some that are normally $3.99 without the sale - I don't have time to check one-for-one, but it looks to me as if the link is producing a few more than were in the Daily Deal, so YMMV...
link:
https://www.amazon.com/gp/search/?se...price-asc-rank