I do know that it is very easy to make tax lien investing sound great but it is a tough competitive business.

You might be asked to pay an extraordinary sum, maybe $5,000, for the program materials or to attend additional seminars and boot camps.Or, you might be tempted by a program that doesn’t cost much only to find out later it is bait to get you to purchase even more expensive products.

In a perfect world it will also allow me to input quotes as well as actual cost to complete each line item, so I can get better with each renovation.

yes, and no-cost basis.

If so what is your cost to build per sq. ft.?

You as a buyer, need to be willing to be competitive in a competitive market, and that is where a great agent will shine.  

It costs me insurance and about $600 in taxes each year.

Don't forget to look at the rental comps as well, closed and available to see what your 'competition' is up to.I always go for a mixture of tough/durable and nice fixtures in my BRRRRs.

We welcome any suggestions or insights you may have Additionally, if anyone has information on the approximate cost of building a duplex and triplex in California, we would greatly appreciate your input.To provide context, neighboring properties in our area offer insights into the local housing market.

Do market research, use real estate tools, account for hidden costs, and build a good team to meet your goal.