This is one of the best apps for expense sharing! Functionally very good, but the UI is a little difficult - but not to complain has all the features I needed.
I just added the people in trips to my contact list (with email)
After the trip export the expenses to them very easily.
Great Job!
Pros:
Functionally Solid
Email Expenses
Free!
Cons
UI - Takes a little while to get used to
Only Contacts can be added as Friend
Deepakssn about PayBack