OH Dan please be careful in where they go. Advertising them as free can attract bad pet owners... I'm not saying all will be, but 'some'...
You have to question why they want a pet yet don't want to pay for it? Vaccinations, food, toys...they all cost $$$ Do they have the funds to keep the pet healthy, fed and cared for properly?
De-sexing is the only way to stop the over population of cats and dogs!!