I hadn't heard of Raider Publishers, so did a check on "Preditors and
Editors" (http://pred-ed.com/) a well-known site where you can check out
possible dodgy sites or organisations in the writing world. They list Raider
as a "Vanity Publisher".
I then Googled Vanity Publishers to find something I could send you on the
subject. Here's one that is straight-forward and tells it like it is:
Basically Vanity Publishers are not well regarded. They are similar in some
ways to self-publishing BUT you have to figure out a way to check up that
they produce the goods - and it costs you a LOT of money. If you're going to
go that way, you would be safer with straight self-publishing or even e-book
publishing. And Val's your lady to talk to in that area.
However I would urge you not to give up on traditional publishing. You're
young and have a long time ahead of you. Now is the time to build up your
platform so that when you get to the point that you ARE ready to publish,
you have a marketable proposal and a presence on the Internet. Start working
on short articles: devotions, anthologies, blogs, etc, so that when you get
to sending out a query letter/proposal for your book, you have a list of
published articles you can give to impress potential editors.
Re traditional Christian markets (and non-Christian) - You're right that
most only want solicited manuscripts, but not all of them. There are some
that are open to new writers.
Re. agents - you should NEVER pay an agent to market your work. This is a
problem here in S.Africa in that the few agents I have heard of DO charge -
so any others of you with a different experience are welcome to shout me
down on this. Overseas agents do not accept money up front. (Some will
charge you for postage, but I imagine with emails today that is no longer
likely.) They get their money out of commission from the sale of your book -
a payment that goes on as long as the book is in print.
Problem is again - many of them don't take on unsolicited writers. Sigh.