If you are strapped for cash, you can first limit your job search to the free sites - Once you've narrowed down your area of interest, create a wah resume (different than traditional) then build a list of at least 6-8 sites like this one who regularly post work at home jobs to get the best idea of what kinds of jobs are available and have a good base of job leads.
Then apply to the openings that you are best qualified for. Best wishes.
Once you get going, or if you are not strapped for cash, I do believe in belonging to a couple of paid job listing sites - for the best chance at landing the best gigs. To me, I just consider the subscription costs as one of the many business expense tax deductions I take come tax time.