AWS Free Tier Termination Projected Costs
Solution 1:
It certainly is not the most intuitive, as you put it, indeed :D The best option I know of is to check your bills for all the items under the free tier and then use AWS Pricing Calculator at https://calculator.aws/#/ to create estimates of all the services you used and sum them up.
For some services that are not listed in the Pricing Calculator (like most VPC resources) you'll have to look them up on their individual product pages and do the maths (googling "aws product-name pricing" usually gets you there quickly...