E-commerce and online shopping

Online shopping (electronics etc.):
Toppreise: e-commerce price comparison
Neptune: New laptops at discounts for students
studyhouse: Commercial Software
Ebay Switzerland
Ricardo: The Swiss Ebay
Digitec: E-Store in Zürich

Books and Stationary:
The ETH-Store

Swiss second hand shop online portal
Brockenhaus: Famous second hand store in Zürich
Brokisearch: Websites/information about second hand stores in Zurich
IKEA Switzerland

Note: Amazon germany is available too, but they do not deliver most items in Switzerland. Books are usually delivered without any issue. However, whatever you order, always verify if they would deliver in Switzerland.