You have several options regarding the textbook for your calculus course.

The text for MAT125, 126, 127, 131, and 132 is Single Variable Calculus(Stony Brook Edition 4), by James Stewart.
These courses also use WebAssign for homework problems and access to WebAssign is required in these courses.

Note that Webassign access is free for the first two weeks and includes an electronic text. So you don't have to do anything right away.

You can purchase the textbook and webassign together or separately; buying them together tends to be less expensive, but not always.
You have several options:

• Buy a physical text and webassign access for several semesters. You can purchase this directly from the publisher for $166.29.
• Buy several semesters of Webassign access with an electronic text. You can purchase this directly from the publisher for $125.00 or from Webassign for the same price.
• Buy only one semster of access to Webassign, with an electronic text. This can only be done through Webassign, and costs $94. This is a good option for students who are taking MAT132 and MAT127, but is typically not a good idea for students in MAT125 and MAT131 (because they usually also take MAT126 or MAT132 afterwards). Many students in MAT126 also take MAT127, in which case it would be better to purchase multi-term access; others stop with MAT126, and should buy only one semester.
• Buy webassign without an e-book. Students can buy the webassign-only access direct from WebAssign. In this case, the cost is $47 for a single term, or $65 for multiple terms.

If you don't buy the e-book with webassign, or a physical book from the publisher, the Stony Brook edition of the text is identical to the book (Stewart's Single Variable Calculus: Concepts, 4th ed, with WebAssign) except for the cover because we made a deal with the publisher to reduce the price for Stony Brook students. This is (or was) the same textbook used in Calculus courses at Suffolk County Community College, just with the different cover.
This might be helpful if you can find a used copy of the text, but these seem to cost about $60 online (without webassign), and so a used copy with one semester of webassign ony saves you about $15 over a new copy with multiple terms (and you can probably sell the new copy for more than $15 at the end of the semester). However, the 3rd edition is very similar to the 4th edition (although the homework problems have different numbers, and some sections have changed a little). Used copies of the 3rd edition can be found for about $10. This might be a good option if you want a paper text for reference, and purchase WebAssign separately.