I wish I had the ability to submit multiple free sites every day, but there are just too many other demands on my time. Looking back over the last 15 months my average is 5.53 free sites submitted per month. I'd really like to at least double that, which my logs show I was doing back in December and January, so I know it's possible. Of course I'd have to ignore some other projects to do that, so the trade-off really needs to be worth it.
Or the short answer... about one a week.