Question about SEO for website?

I want to create an online boater exam course. There are currently 2-3 online courses (you have to be approved by a national ociation) which offer a course leading to a boating safety certificate in the 42 states which offer one. The material is straightforward and there is not much difference between the courses; I have a different approach to wrong answers and review of material which will make me competitive, but not superior; to the others. My question is this: I don't know how the other sites (found by Googling boat exam or boat course) advertise or do SEO, and I need to know what I would have to do with either SEO or a "sponsored site" to get my site on the first page. (There isn't any affordable way of advertising off the Internet.) Also I need to know the probable cost per month of such SEO or "sponsored site" or other Internet advertising.