Good question. But it depends on the server. The more populated the server, the more expensive the houses are.
I will give you examples on the most populated pvp server which is Antica.
The houses on Issavi have been auctioned for a high price. I heard from a friend that one of them was auctioned for 120kk!
It's a crazy price but yes, Antica is one of the older servers, there are a lot of people here, and homes can be very expensive.
I think Yalahar is one of the more expensive cities and houses. Houses in this city reach the border of over 100kk+.
For example :
Fortune Wing 1 - the biggest house in Yalahar. I think there are people who pay about 200kk for those.
Luminous Arc 4 - roughly the same price as for the first
Luminous Arc 1 - certainly this house will reach a high price!
The same applies to some homes in Venore (50-100KK) and Edron.
One of the most expensive of this city are :
Central Circle 1 - this is one of the most desirable homes. I think this house on Antica is worth about 200kk!
Central Circle 2 - Price similar to the first house.
Wood Avenue 7 - I think you would pay a minimum of 100kk for this house, certainly more, but gives the minimum price.
About the houses on Oramond I will say only that they are not as expensive as other cities but also reach the 100KK border. It depends on the location.
It also depends on the location and server. I will add that it is very hard to buy a nice house on Antica. For this people are able to pay cosmic sums, the more that money goes in an easier way to get in this game.