I'll let someone from LA county try to answer your question, but I am curious how much a vacant lot cost if the homes are selling for that amount.
You can buy a nice new brick home in my area for approximately $100 per sq/ft. That's on a half acre lot.
I just can't imagine the construction cost are going to be 300% more there vs here, so I'm guessing the lots values must be highly inflated.
Here it's pretty cheap to set up a lot. Even if there is no access to city infrastructure. Power hookup is usually free if there is access within 1/4 a mile, Water well cost about 3K, Septic cost about 3K. There's your utilities for $6,000
A Forestry mulcher could clear a 10,000 sq/ft lot in about 3hrs so about $375.
A D5 dozer could level out a 10,000 sq/ft lot in a day. There's another $1,000
Concrete driveway for a lot that small maybe $5,000
So for $15,000 everything is done and ready to start building. That amount will probably cover your first permit in LA county lol...