Seeking subdomain usage and related SEO advice...  I'd like to use multiple subdomains for multiple landing pages all with content related to the main root domain. Why?...Cost: so I only have to register one domain. One root domain for better 'branding'. Multiple subdomains that each focus on one specific reason & set of specific keywords people would search a solution to their reason to hire us (or our competition).

Can I use MOZ for initial keyword research?  Can't create an AdWords campaign (no website yet to register) to get use of Google's Keyword Planner & my subscription to Wordtracker is showing me too many unrelated keywords... Peter