(Your topic has been moved to different category with changed title for let other users find an answer if they will have the same as yours question.)
While Webflow do not nave such function, users on the forum found workaround for create such functionality.
For create filter/sort option for users on your blog you can use tabs widget.
On every tab pane you can add dynamic list and sort/filter it with particular option. Every tab-link will have a title which will show the option.
"All" - Dynamic list without filtering
"Free" - Dynamic list filtered by "tag" field with value "free"
"Paid" - Dynamic list filtered by tag field without value "free"
Same with sorting.
So basically you are pre-filtering content and put it to the different tab panes. User click on tab-link and choose what he needs.
Only restriction in this workaround - no more than 10 dynamic lists on one page