Splid - Splid helps friends manage their money.
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!
Tricount - Manage and share expenses with friends
Nextcloud Cospend - The Nextcloud App Store - Upload your apps and install new apps onto your Nextcloud
Splittable - Shared living made simple
LetsPayTheBill.com - Free online tool to calculate the distribution of expenses during a group activity.