Hi @meow,
For SPICE the only cost is the per GB charge. SPICE can be queried as much as you want without any additional charges. 
If the data in SPICE needs to be refreshed with new data, then you are interacting with the underlying data source to do the refresh e.g. Athena + S3… then you will be charged for that query. However this will be a single query to load all the data in to SPICE on each refresh (incremental refresh is also an option), and not multiple queries like you have if using it as a Direct Query dataset.
For example you can see here I have a SPICE dataset in Quick Sight using an Athena Data Source, it is set to refresh every hour, so there is one query an hour, that incurs a small amount of cost.
If this was a direct query data set there would be many queries to Athena for each dashboard load.
Hope that helps.