This section of YT is for yorkies who need rescued or rehomed. If you want to buy from a breeder there is another section for that.
You could check your local shelter...some having waiting lists for purebreds. So you could go on the waiting list, and when they get a yorkie in you can adopt him! You should look into adopting one before buying from a breeder, if you can afford the medical care they may need. That would give you time to research everything you need to know