Context: I am an assistant professor of mathematics at a small institution in the US.
Our department uses Stewart's Essential Calculus for our calculus sequence, but I find that my students and I are definitely under-using the book.
In particular, I only use the text to assign "suggested problems", which are simply practice to help my students prepare for quizzes/exams. As such, Stewart's book is not of significant enough value for students to be willing to buy it, which means that many of them study less than they probably should.
This brings me to my question: Are there cheaper texts out there that are merely "workbooks"--just lists of practice problems with answers? I'm hoping to find something that students could buy for less than $40 that would correspond (at least somewhat) with the material in Stewart's text.
(I still assign graded homework problems that I write myself, but I don't currently have the time to write practice problems too.)