Fubajit is a shopping calculator, geared towards helping people (like me) track their shopping expenses while shopping, in order to ensure the budget (food budget!) is not exceeded. There are some apps out there like this, but I hope to have added features and usability to make this app stand out. Check it out! Currently on Android only:
https://play.google.com/store/apps/details?id=net.irrer.fubajit&hl=en