The plan I am following...
1) Plan a series as your debut
2) Release book one for FREE.
3) Get real honest people to review it and post reviews
4) List it every where you can (Smash helps get you in a lot of places, Amazon lets you self list, etc).
5) Promote the book on every site that will let you. Do not count on others to promote for you.
6) Release Book 2 at $2.99
7) Repeat steps 3,4,5
8) Release Book 3, judge price by demand that book 2 generated.
9) Repeat till you retire from writing.
This of course assumes your books are good and worth buying. This is a MULTI-YEAR plan to become successful. You need to build a name for yourself and create a demand for books with your name on them before you could get away with a $5 or $10 price tag.
That is my advice. Might be worth as much as you paid for it....