In Monopoly Deal, can you pay with houses or hotels?
From the Monopoly Deal FAQ (scroll down to near the end):

Q - WHICH CARDS CAN I USE TO PAY OTHER PLAYERS? (E.G. FOR RENT, BIRTHDAYS ETC.)
A - You can choose to pay:

from your Bank (with money or Action cards that you've Banked as money),
with Property cards, or
with a combination of both.

Remember, you can only pay with cards that are on the table in front of you, never with cards from your hand.

You cannot pay with Houses or Hotels you have on properties because they are not in your bank nor are they Property cards themselves.  If you had Banked them, you could use them to pay for things.