Loot
Online version of classified newspaper with advertisements in over 400 categories. Sell or auction free of charge.
http://www.loot.com

Sell It Yourself UK
Free adverts and searching service. Includes classifieds, boats, property, cars, jobs and business directory.
http://www.siyuk.com

Student Advertiser
Students can advertise items for sale, place wanted adverts and contact other members.
http://www.studentadvertiser.co.uk

Studentswapshop.co.uk
Classifieds exclusively for university students, sorted by university.
http://www.studentswapshop.co.uk