I vaccinate my own puppies before they leave me, and I get mine here:
Revival Animal Health Products for Pet Professionals, Veterinarians and Pet Lovers
My vet says they are all pretty close in function and prevention once you get past the cheapies, but someone else might have a different opinion...
If you've never done it before I would get your vet to show you exactly how, on a small yorkie it's easy to accidently puncture something if you're new at it...
