Well, not entirely sure what your friend is talking about, but there has always been research into 'birth control' for cats...whether they are effective or productive measures, there isn't enough research or data to support it thus far. Even if birth control products were available, they would not prevent common problems and diseases which can be the result of not spaying or neutering. (pyometra, uterine cancer, mammary cancer, testicular cancer, etc). So, try to convince her that spaying/neutering is the best option all around.
Love Your Pets - Spay and Neuter.
As for reduced costs of spaying and neutering, almost every community has a vet or organization who will have a spay/neuter clinic event for the community. Some shelters require it before adoption, and some vets will spay/neuter with a valid voucher from the shelter. My advise is use a small animal vet's services, because with a spay/neuter clinic, you cannot guarantee monitoring after anesthesia, followup care should there be problems with recovery, etc. A primary vet will provide these options and your pet's safety is paramount.
I think most of us would agree with the statement...if you can't afford to spay and neuter, let alone exams and regular veterinary care, then one should not have a pet. Pet ownership is a responsibility and a priveledge, where the pet is dependant on the owner to do right by them.
when my neighbor told me of this so i am ready for all the laughter......so with that i was told there was a "shot that can keep a cat from going into heat its like birth control for cats"..........ok i will let the laughter go........is this one of her "alien" theroies or has anyone heard of such a thing. 
