I’m not a video editor, but I can share with my past experience with hiring video editors. The cost of editing a 5-minute video can vary quite a bit depending on factors like the complexity of the project and the experience level of the editor. Typically, I've seen rates ranging from around $50 to $250 per hour or more, with an average editing time of 2-3 hours for a 5-minute video. So, I would expect the charging to somewhere in the range of $100 to $750 for 5-min project. The range is big of course. It's always good idea to communicate your budget and expectations upfront, as pricing can vary widely depending on the specifics of the project.
That depend on what kind of editing. There will be different charge for just simple adjustments (improving quality, colours etc.) and different one for more complex project like synchronizing audio, adding titles, subtitles, creating custom intro etc. $10-20 a minute on average.