It all depends on the size of the home (building permits are calculated by the sq foot of the home), if it is located in Coastal Commission's jurisdiction (much more expensive and much more time for permits/years) or not, and many other factors. A good thing to do is to contact a local architect and show him/her the lot and get an estimate on those costs. The architect will have approximations for the perc test, engineering, septic, water meter, electricity hook up, and other costs. They could pull up a previous job that is similar and give a good estimate. Are you looking to build in Topanga? Prefab or kit homes is a good way to go as the upfront costs are known as far as the structure is concerned. Checkout deltechomes.com and formandforest.com
If you are looking for a property in Topanga, I own an acre property of 4 continuous lots that has a great view of Big Rock and surrounding canyons, has a street, water, power, perc test, topo map, geology study, septic, engineering and architectural plans. This can save you tens of thousands. I now live in Orange County and will not be building on my property. I am letting it go for less than 200,000. Come up to see the property and make me an offer. It's one of the last buildable acres in Topanga that is out of Coastal Commission.
You can email me at email@example.com if you have any further interest.