Is a free tool that allows you to get a deeper insights of your billing and have granular views and filters by service, tags, region, usage and so on and identify your main cost drivers.

You can have daily and monthly views for free ( or you can enable Hourly view at a cost).

In the Advanced Options you can view costs as:

unblended costs represent costs on the day that they are charged. This is normally what we as developer/leads will look at to monitor daily and monthly spend or find spikes in usage/cost

amortized costs distribute costs evenly across the month to avoid spikes related to recurrent fees like reservations/saving plans

amortized/unblended net costs are similar to the above but include discounts

blended and amortized costs

Cost Explorer shows data up to the past 13 months and can forecast your expense over the next 3 months.