Has anyone had an estimate done for Invisalign for teeth that only need minor correction? I had braces as a child but of course my teeth have shifted some as an adult

I have a small gap (really not that noticeable) but it drives me nuts, so I want to get it fixed.
Wondering if cost for Invisalign might be less to correct such a small problem? Or maybe an orthodontist could just do a retainer to fix? Anyone gotten estimates for orthodontic work that wasn't metal braces?