Bernie, you cannot get a dog for $150 anywhere else as far as I know. A rescue dog will set you back $350 here, might be a bit cheaper in rural areas. Of course, usually that is to cover the vet costs for desexing and vacciations. And any money that might be left over, will go back to the rescue organisation.
You still get people giving away dogs for free in the classifieds of course. I agree with others that it is risky and asking money for them might at least weed out some of the irresponsible pet owners. It's just a shame that in this case that money might go to an irresponsible pet owner!
And New1: recently an ad appeared in the local online classifieds of a person wanting a dog for free, desexed and vaccinated, house trained and with basic obedience training. She didn't care if it didn't come with food (this is true!) but would prefer if they came with their bedding and toys. She admitted to having no money at all. The ad went on like that and it was very clear this person should never own a dog (someone posted on a forum that they knew here and that she had mental health issues). Someone reported it to the RSPCA here who contacted the person and convinced her to take the ad down and consider maybe adopting a cat instead.