So assuming a price to rent ratio of ~10 (like modern day Japan, it'd be lower if interest rates are high or if loans are difficult to get), then the House costs roughly the same as Roxanne.
Actually, from this it kind of looks like in this world, the value of 1 nar is roughly equivalent to 1 dollar, for large purchases or investments? That means that his labyrinth income was equivalent to roughly $1k per day (with Durandal making him OP and almost risking his life ofc), which is comparable to what say, a Blackwater mercenary would make.
Overall the economics of this world look well fleshed out.