The only advertising I did was in the Sunday paper (one day), probably won't do it again, as you said, it was expensive around $50.00 if I remember right. And also the Trader Paper, you can add 4 pictures for like a month I think, and it was only $42. I did receive a few calls, but when I put up big signs on two highways close to us, the calls came pouring in. I had a lot of interviewing to do....LOL (I used plywood, painted it completely white and then used black or dark brown paint for the lettering and sprinkled glitter in it so it would show up at night.) All my boards said was: For Sale, AKC Yorkie Pups and then my phone number.
Have you tried the online newspapers? or Radio stations? A few of them are free online.