Welcome to YT.
Just glanced at the site.
No such thing as teacups (marketing term to get more money).
Smaller pups shouldn't have a higher price than bigger ones really. They are more fragile.
There is a "buy it now" option which is absolutely unacceptable. They should be screening buyers thoroughly.
They will sell as young as 8 weeks. The recommended age is 12+ weeks for Yorkies.
It looks like they are guessing on adult weights too early.
They have a 7 day health guarantee with loopholes. You want at least a 1 year health guarantee against congenital defects.
This place looks very concerning.