The hardest part of living with roommates? Other than the standard dirty bathroom sink, it's the semi-awkward monthly bills money collection. Throw out the whiteboard, stop leaving overlooked Post-its, and give bill-splitting a 21st-century upgrade. Remind roomies you need to be reimbursed for toilet paper and evenly split your weekly bonding dinner with the best apps for splitting bills and living in roommate harmony.
Splitting bills doesn't get much easier than SpotMe for iOS  (free). Add photos of the bills or groceries, specify exactly how each bill should be paid, and send gentle reminder messages to the whole group or an individual. It'll also remind you when you are the one who owes money.
Is it possible to feel a sense of zen when paying bills and tracking down money from friends? Splitwise certainly makes it seem so! Free for both Android  and iOS , the app makes the trickiness of money less stressful to navigate; use the fairness calculator for everything from how much each roommate should pay in rent to what that old couch should be listed for on Craigslist.
For the nights you take the roommate bonding out of the house, use Billr on iOS  (free) for splitting one-off dinners right down the middle (or three or seven ways). List the cost of each dish, account for split appetizers, and work in tax and tips to the final total. It works with all currencies, so you can even divide the bill for a luxurious dinner in Paris.
Built for iOS, Divyit  (free) is arguably the prettiest of the bill-sharing apps, with bright icons and a clean design. Add an unlimited number of participants to each bill group, who will then be color-coded with the option to send gentle email reminders that rent is due.