This Learnvest article mentions a few apps for splitting bills that I hadn’t heard of.

• Splitwise: If your group is taking turns covering expenses (“you get this dinner; I’ll get the next”), track them with Splitwise. This app keeps a running total of who’s covered what, so you can settle the difference at the end via Venmo or PayPal.
• Billr: Perfect for large parties, this app lets you split a bill with up to 16 people so each person pays for what they ordered, plus their portion of any shared items, tax and tip. You can also send each person a copy of the split bill in a text or email.
• Divvy: Snap a photo of your bill and drag each item to the appropriate person (uploaded through your contacts) and Divvy will automatically add up what each person owes, plus tax and tip.