Having a free option sounds like a bad idea. Given that your users are by definition people interested in investing money, they should be perfectly suited to pay. Really what they're paying for is time, since they could find all of this info on their own, but their time is worth more than $20 to do so.
Edit: But I do like the idea of a free trial for a week or a month.
Edit: But I do like the idea of a free trial for a week or a month.