@Prathmesh Chopade Firstly, the charge is actually for your app service plan and not your application itself. So even when you stop your web app, you will still be charged for the resources allocated.
Also, note that there will be additional charges for supporting resources as needed like Azure Monitor. Please feel free to read this doc that explains costs for App Service.
So, here are the answers to your questions,
How much mac it can cost per day for B1 plan?
You will be charged if you have an app service plan created (other than free) and it is prorated to the second.
as B1 plan is for 4299 INR, so will it cost more that this? if all resources used?
I assume this is the monthly price shown on the pricing page. If so, this is the amount you should expect at the end of the month for your app service plan.
If my app service is stopped, then average how much should it cost per day?
The plan itself cannot be stopped. You will be billed if it is not deleted.
Some of these questions are also covered in the FAQ section of the pricing page.