Roomie-Pay lets you pay for stuff in groups! Roomie-Pay integrates your Venmo account and allows you to make purchases for a group, and then have group members pay you back.
This is perfect for roommates: lets say you buy paper towels for your apartment for $6. Open up Roomie-Pay, select your roommate group, and enter a charge for $6 for paper towels and bada bing, bada boom it splits the $6 cost evenly between your roommates and sends out Venmo charges automatically.