On way to Barbarian Village, just past the big bank when leaving varrock.
They are found on Doogle Bushes on the ground south of Gertrude's house (just west of Varrock)
no you can not sell your house on runescape.
No, Your RuneScape House is based on your Construction Level.
Camelot
Go to the place with the house icon in varrock.
in the volcano at michaels house
open the door
Yes.
Yes.
you build on your house
yes
No.