Purchasing leads is a waste of time and money. You are better off investing in an outbound system, e.g., a blog, an outsourced CRM that tracks your clients birthdays, anniversaries etc. Every industry has an expert in this arena and for mortgage clients, Outbound Engine seems to do a decent job. I have also recently found that blogging in Q&A sites works the best even though it does take a bit of time.  As a matter of fact, this site has become my favorite; the quality of the questions is excellent and often makes you pause and think before you answer, triggering more questions and ideas.