I agree that you should not chare a smallfee - you are setting yourself up for complications in the very near future. Yo uare better off to draw in fewer people, more slowly. You will get the same amount as if you charged half the fee for twice as many people. Also, bringing students in more slowly ives you the oportunity to focus on developing teaching styles that work for you and to work out learning sequnces, etc.
Also, if you charge less, it is true that people will take advantage of you - thinking you are not as professional and therefore not deserving as much respect. It's not deliberate, but hink about it - if you were choosing to buy a product, would you not expect htat the cheapest one was not as good - especially if there is a big price difference? At the moment, you are probably jsut thinking youwant to make a start, so it doesn't matter. However, speaking from experience, don't do it!!!! You need to find out what other teachers around you charge, and perhpas charge a little less if you woudl feel more comfortable that way.
I advertise with my education credentials, but I have never actually ahd anyone ask what my qualifications are. People do ask how many students I have of different ages. The best way to deal with that is to be honest - tell them you have just decided that you would like to work full-time as a teacher, but if you have given lessons in the past (even her and there), it's OK to mention you have taught on and off for X number of years.
You may well be surprised how quickly your number of students builds up. I find most new students are beginners, but perhaps you might say you specialise in beginners. That way, you can avoid feeling liek you might take on aomeone at a level you can't handle. Also, if people do ask about your credentials, perhaps you could say you are working towards your teaching diploma - or somethin similar.
Word of mouth will eventually become the most productive net for new students. Until then, use any free advertising you can find. I got my first 3 students from a community notice board. One term's advertising in school newsletters was also worthwhile, but expensive for starting out.
Good luck