Here is guidance from Lolth:

“On the main streets they were 5 or 6 silver per tile, on the back streets 3 or 4. I forget if it was 4 and 6 or 3 and 4. I would err on the higher side. They were intended to be a coin sink.”

We charge for tiles on a per floor basis, as a two or three story house is more space and should be more expensive. Ballpark: A smaller house might be 40s, a larger home upwards to a 1g. One of the biggest homes in Mythmoor, Perry Manor, cost me 1.2g or 1.3g, if I remember right. Lolth sold it to me. Average house size is in the 60s range. Ultimately, the price is negotiable and up to the GM.

It's not necessary, but I've started giving out writs of ownership. I create a blank paper with the name “Writ of Ownership of <insert house number and address>” and then write with a reed pin and ink something to the effect of “This document is to certify that <GM name> sold <address> to <player name> on <date>.” It gives the player something to keep and serves as an official record as the inscription is signed with the GM's name (a property of the paper itself, not the inscription text) and cannot be forged.

Lolth:

“Also any player who has been absent 6 months or longer you can take their home back, the only exception I ever made was with past GM’s, I left theirs indefinitely.”

Thus far we typically only revoke ownership if a player is interested in a home and the current owner hasn't logged in for a long time, but again it's up to the GM. I know I have had at least one player come back to find their home owned by another player, and I had to set them up in a new home.