Have you ever submitted FS before? There is a learning curve there and I don't know too many people who submit daily. Even if you find a site that converts well for you (and that's not always easy), you have to vary your niches and can't submit to the same one daily, so you're not likely to keep that great ratio through out the week.
BTW, even a simple question as how many clicks a FS sends to a sponsor isn't that easy to answer. It depends not only on the niche, but also on how your sponsor counts clicks

I've seen anything between 200 to 5000 clicks to a sponsor from a freesite (and that doesn't mean that the 5000 clicks one made more sales

).
Some sites never make sales, but I would say the average is about a sale per FS. That's after almost 2 years or building and submitting, and with my FS being accepted by most of the larger LL's.