Selling: Econ 1, CS 103, CS 109 textbooks

I am selling the following books:

Principles of Economics 6th edition, USED - Good, 40$

http://www.amazon.com/Principles-Macroeconomics-John-B-Taylor/dp/061896763X/ref=sr_1_1?s=books&ie=UTF8&qid=1390175397&sr=1-1&keywords=principles+of+economics+taylor+6th

Discrete Mathematics and Its Applications 6th edition, USED - Like New, 40$

http://www.amazon.com/gp/offer-listing/0073229725/sr=1-4/qid=1390175483/ref=olp_page_2?ie=UTF8&colid=&coliid=&condition=used&me=&qid=1390175483&shipPromoFilter=0&sort=sip&sr=1-4&startIndex=10

A First Course in Probability 8th edition, USED - Like New, 70$

http://www.amazon.com/First-Course-Probability-Sheldon-Ross-ebook/dp/B005H8D88G/ref=sr_1_1?ie=UTF8&qid=1390175643&sr=8-1&keywords=A+First+Course+in+Probability+8th+edition