Splitwise - Splitwise is a free tool for friends and roommates to track bills and other shared expenses, so that everyone gets paid back. On the web, iPhone, and Android!
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Tricount - Manage and share expenses with friends
Cvent - Cvent's event management software provides event planners with a complete solution to increase event attendance and decrease event costs.
Kittysplit - The easiest way of sharing costs with a group of friends
Ticket Tailor - Ticket Tailor is an easy-to-use event ticketing platform that allows event organizers of all shapes and sizes to sell tickets online.