Malarkey 30-Year Dimensional Shingles.I have gotten estimates ranging from $5,500 - $7,500, which all seem like total rip-offs to me given the small size of the house.What do you think?

I wasn't unprepared—I had a clear idea of my MAO,  ARV, and estimated repair costs.

@Pandu Chimata You may need to start getting estimates if you're planning to add infrastructure to the vacant land.

What was missing was a estimate for what he recommended. 

Could anyone provide advice on the most cost-effective way to construct this and tips on estimating the total cost?

Currently we are renting in a city of Orange Co California, where the rent and property prices are higher, however we need to live here due to staying within the school district for my son for at least the next 4 years.Recently we sold some property overseas and have approximately USD $400K in cash.

I want to ensure that I follow any sort of regulations and safety standards but I don't know where to even start or know how to estimate rough costs.

A buyers agent, even if compensated by Broker for Seller, will represent the interests of the buyer.Under : "Sellers Estimated Costs" she's got me paying $1,925 in fees. ($675 preparation of deed) ($650 transfer tax) ($300 settlement fee) ($300 notary fee)Also in "Sellers Estimated Costs"  "brokers fee" is listed as "$4,000"   rather than 6% or $4,000 as if the 4k is just a flat rate.I feel this gives her no incentive to sell my property at the highest bidder.

My realtor/PM says $0.95 to $1.05 per sq. ft. is a reasonable monthly rent for a 4 BR/2 BA property in that area, which (according to the BiggerPockets calculator estimate I did) is enough to cover the monthly payment plus the above costs I mentioned.I anticipate putting down my deposit and earnest money in the next few days. 

I do not have much knowledge on real estate but I am the hitting  books: BRRRR by David Greene, Estimating Rehab cost by J.Scott, Investing real estate with no/low money down by Brandon Turner and finally, Rental property investing by Brandon Turner.Outside of real estate, I enjoy swimming, bike riding, watching anime, playing video games and interests in the stock/house market.Excited to learn and connect with you all!