I haven't read the other replies, but I'm sure someone has already mentioned it - there is no such thing as a "teacup" Yorkie. This is just a term that breeders use to sometimes jack up the prices of very small Yorkies - however the AKC does NOT recognize the term "Teacup" - really, this term is only used to describe the "size" of how small a Yorkie is. I understand if you did not know this if you are "new" to Yorkies.
Also, good luck on finding one that someone is just going to GIVE to you
Yorkies aren't cheap. If you are looking to buy a puppy, I suggest that you start SAVING UP
However, there are many, many Yorkies (and other breeds for that mater) that are in shelters that are in desperate need of rescue - so if money is an issue with you, then rescuing one might be your best option (and a good one at that). The chances are slim that you will find the "Teacup" that you are looking for if you do decide to rescue - but size really does not matter. A Yorkie is a Yorkie is a Yorkie and I PROMISE YOU - you will fall completely in love with it no matter what it's size is
Good luck!