Buying drinks and snacks in your hacker-/maker-/foospace is easy with ACKbar.
Don't burden your participants with calculating change; math is for nerds. Instead, create an account and enjoy the benefits of having an account balance.
Accounts don't have passwords because it didn't make sense for our usecase.
Run with 'python app.py'
python 3.6+ sqlalchemy pymysql
Change username and password in credentials.txt file. Uncomment one of two SQLALCHEMY_DATABASE_URI lines in 'database.py' to use either mariadb or sqlite.