Here's a major low tech way, but I know it has worked for some of my friends... on one ad put "ask for Tom," another "ask for John." etc. lol... worked well for him!...I like Callfire too, $3/3 months of a number, plus 5 cents a minute. Pretty damn good rates. I can recommend Callfire, Google voice is good too and free, but getting more than one number is a pia, max you'd easily get is probably 2, using your home phone and cell phone. Throwaway digits could also work, I believe you can get some of em for less than $1/month.