What Am I Riddles

Question: You put me in dry but then I get wet.
The longer I stay in, the stronger it will get.

What am I?

Question: For now I must stay under the man who made me,
but when he dies I'll be as powerful as he.
They will watch and listen to what I say,
then some of their money to me they'll pay.

Who am I?

Question: I live off of a busy street,
if you want you can stay for an hour or two,
but if you don't pay rent I'll tell on you.

What am I?

Question: I have roots that nobody sees,
I'm taller than any trees,
up and up I go,
but I never grow?

What am I?

Question: Thirty white horses stand on a red hill,
First they champ,
Then they stamp,
Then they stand still.

What are they?