This page helps you decide whether you should buy an Inverter AC or a Standard one (i.e. Non inverter).
You have to consider many factors when you are deciding between Inverter and Standard. For example, comparatively Inverters keep the cooling rate constant and uniform, which is more comforting than the Standard one. However this page only compares the pricing difference and electricity units and helps you decide whether its 'worth' to buy an Inverter or not.
Usually Inverters are said to be 30% - 40% power efficient than non inverter ones. In below calculations, it assumes that Inverters are 20% efficient than Standard ones. You can change this parameter if you know the efficiency.
As you can see, you will save about Rs. 0 per year with an Inverter AC and it will take about 0 years to recover the extra amount you have spent on Inverter.