One of the Twitter accounts I follow suggested ProWritingAid as a tool for editing and polishing your writing. After checking out the free version and really liking how it worked I went ahead and downloaded the 14 day trial of the professional version. At the end of the 14 days they have different payment plans. The cheapest is $50 for one year. My friend who is an editor charges $50 an hour and is for basic editing. This program looks at grammar, spelling, pacing, style and a variety of other important editing advice, covering several different levels (types) of editing.
Note: The professional version works in Microsoft Word.
I am not getting paid to advertise for ProWritingAid. I believe this program is one of many out there that can help a writer who is self-publishing and does not have a ton of money for a professional editor. Hopefully if you try out this program it works for you or you find another program which fits your needs best.