You might want to do some research on your potential customer base. For
instance how are you going to promote your magazine? Is the cost of promotion
going to kill any profits you might make? How long is it going to take to get
off the ground? To whom are you going to promote your magazine? The
publishing industry is struggling as it is in much larger markets. It might
be extremely difficult to build a customer base even if you give it away.
You probably won't be able to answer these questions although you should
probably at least think about where you are going to promote it and to whom.
Figure out how much that will cost.
Google is probably going to be prohibitively expensive. So are most other
routes of advertising. Maybe you can get it bundled with a larger magazine
some how. I'm not sure how that would work with an e-publication though.
Maybe you can find web sites of a similar topic to help you with promotion.
Give them a cut of the profits and go from there.