BitStack is a Bitcoin savings account app that makes saving in Bitcoin simple, fun, and effortless. Based on the concept of automatically rounding up bank transactions to the nearest euro (e.g. a coffee bought for €2.60 is rounded up to €3.00 and the €0.40 is put aside), savings are created without any extra effort. The small change is accumulated throughout the week and then automatically converted into Bitcoin the following Monday. Additionally, users can take advantage of the recurring savings feature (allowing them to automatically save the amount they want every week, every fortnight, or every month) and the one-click purchase of bitcoins with a bank card, starting at €1.