I have some configuration data i want to read from the spring boot application. The configuration can get bigger and bigger, therefore i dont want to create yaml file in the project. I was thinking about what would be the cheapest way to save this data in AWS. Like DynamoDB? or do you have maybe better and cheaper ideas?
DynamoDB would be a good solution, it will allow you to quickly retrieve and edit the config set. DynamoDB also has a free tier of 25RCU/WCU and 25GB storage per month, which I assume you will fall into that category making it a free option.
The only limitation with DynamoDB is that 400KB is the maximum item size, however, you can split your item up into an "item-collection" where all of the items share the same partition key and the sort key identifies the sub components.
AWS App Config is the correct service to use for application configuration setup but it is not cheaper than using DynamoDB for free, so your trade off is down to what you need from your configuration data.