As a relative newb, my 2 cents may be worth just that...
But, I plan on doing an eBook only giveaway for my eMail Scraper product since it's hard to do a video showing how to use the software and a demo tutorial is already on the sales page.
I have been working on putting together my own eBook / videos for basic SEO training. For that I would think that a free video AND ebook would be better since an ebook and videos are what they get in the course.
HINT: As of a efw weeks ago, I had never made a video. I downloaded Jing for free and used that to 'practice' on. Like some have said in previous posts, create a simple PowerPoint presentation and narrate the slides. The cool thing about Jing is that it's totally free.
Another piece of advice is to practice doing narration / demo videos on something you are VERY familiar with first. This will help you relax and develop your speaking style and pattern since you are familiar with whatever your doing in the video. It's hard at first, but listen to your narration in the video. The self critique works very well and makes your presentations better over time.