Clarification Needed on AWS Business Support Plan

Question

I have a full stack application running entirely on aws. We get ~200usd bill per month. I am looking to upgrade support plan especially to use AWS Trusted advisor. 
I am confused by the support plans description. 
It says 
"The minimum monthly charge for the Business plan is 100 USD, due at the beginning of each month".

Does that mean I will be billed extra 100 usd ie 300 usd per month?
or
I can use the business support plan as I get 200 usd bill without any additional charges?

Please explain on this.

Answer

Hello.

In your case, I think you need to pay 100 USD for the support plan.  
https://aws.amazon.com/premiumsupport/pricing/?nc1=h_ls

Business support is at least 100 USD, but if you are using an AWS usage fee of 10,000 USD, you will be charged the higher of 10% of the usage fee and 100 USD.  
In other words, in your case, 10% of the AWS usage fee of 200 USD (20 USD) is compared with 100 USD, and since 100 USD is higher, 100 USD will be charged as the support fee.

Clarification Needed on AWS Business Support Plan

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