The problem with purchasing water anywhere is you have no control over its quality and do not have any idea of that quality unless you have a TDS meter.
If I must purchase water I always buy it form a staffed Water & Ice type store so there is a live person there to answer my questions and test the water in my presence. All the stores have conductivity or TDS meters and are more than happy to test it for you. With a machine you have no idea when it was last serviced, what that service was or if it even happened at all. Most States and Cities have no regulations for water vending machines other than weights and measures for quantity, not quality.
Nothing replaces having your very own RO/DI unit and meter so you alone control its quality!