That’s a good price, tanmay. iOS has an inbuilt battery indicator for connected bluetooth devices that shows the battery life as an icon in my iPhone’s taskbar, and also as an actual figure in notifications (see pix). It’s not very accurate but it’s better than nothing.
Android on my Mi4i does not have an equivalent that I know of. But there’s workaround via an app called Bluetooth Headset Battery. Here’s the link in the Indian Google Play store in case you want to try it.