I use http://captainc.veretekk.com and do about 50,000 ads a month.  It is a vast system with autoresponders, a marketing center, traffic portals, a weekly newsletter and much much more.  I spend about 5 to 10 minutes putting together my newsletter that reaches 14,000 so far and growing.  I get about 10,000 leads a week and out of that 20 to 50 verifications.  With each newsletter etc., I get more leads to call than I can possibly handle.  The system also makes money for you along with your primary and other businesses.  Worth the trip to check it out.