Grammar and spelling errors are a great way to ruin a first impression. Don't take that chance!
I am a grammar fiend. I will nitpick every comma, use of the subjunctive, form of "who," and anything else grammar-related in your document of 1000 words or less (2 gigs for work up to 2000 words, 3 for up to 3000, etc.).
I can edit in a Word/LibreOffice doc or Google Doc (my preferred method), or you could even mail it to me and get it sent back to you with my multitude of red marks and comments.