As a librarian, access to WEXIS (librarian speak for Westlaw & Lexis) is amazing. I rely on these databases for most of my research needs.
However, if I were to start my own little solo practice, I'm not sure that I would be able to afford WEXIS. In the alternative, I might rely on a low-cost database, such as Fastcase or Casemaker.
For premium access, Fastcase costs $95/month. And some jurisdictions give 'free' access to Fastcase through the state bar.
Something that I really appreciate about Fastcase is its extensive free webinar series. The webinars cover the following topics:
Introduction to Legal Research on Fastcase 2014
Advanced Tips for Enhanced Legal Research on Fastcase 2014
Introduction to Boolean (Keyword) Searches 2014
Introduction to Legal Research on Fastcase for Paralegals 2013
Casemaker is another low-cost database that the State Bar of Michigan (as well as 24 other states) partners with to provide 'free' access for its members. If your state bar does not provide access, the premium subscription costs $45/month.
Casemaker also has a free webinar series to give you an introduction to the basics of the database.