Another great app for tracking expenses is Splid [1] – IMO much better than Splitwise, no accounts required, clean and beautiful UI. (I'm not affiliated with this app)
[1] https://play.google.com/store/apps/details?id=splid.teamturt...
[1] https://play.google.com/store/apps/details?id=splid.teamturt...
and the website (no web app ATM): splid.app