It is not someone I would recommend to buy from. Teacup is a marketing term, there is no such thing otherwise. Also selling champion lines by someone who doesn't show is a red flag they do not know much about the breed.
There is a little female pup for sale, looks like size will be 4 lbs estimated and will sell on open papers for a higher price.
Check out the YTCA breeder list
Yorkshire Terrier Club of America Any breeder you talk to should be willing to answer any questions you have but way more important should be asking you a lot of questions about what you are looking for and the kind of home you can provide, previous dog/pet ownership.