To prevent abuse or misuse, Amazon SNS sets your default SMS spending limit to US$ 1.00 per month.
For example, let's say most of your users are in India where SMS costs US$ 0.00223 per message. You estimate you need to send about 50,000 SMS per month. This will cost you US$ 111.5.
So you might want to request a slightly higher spending limit, say US$ 200.
That’s it. AWS will take a few hours to respond. If AWS needs any extra information they will ask you for the same before increasing your spending limit.
Do not worry if AWS gives you a lesser limit than what you asked for. Just send a few SMS, wait for a few days and submit another limit increase request.
Over time, depending on your usage and reputation, you can continue asking AWS to increase these limits. They will do so gladly but only if your sending reputation is good. So make sure you don’t send out any spammy SMS's.
Once AWS grants you your SMS spending limit increase, you will need to input that value in Send With SES (see below image).