Thanks there's no need to rush in real estate, especially in today's environment.

Essentially I want to know how to evaluate home value when market value is difficult to know in today's environment?

That said, I would recommend to see what your state guidelines/regulations are. 

I have no familiarity with HELOCs but I believe most of them are only available to owner occupied properties in the current lending environment.  

City regulations and other rules may change at that time.

On the long term financing/refinance, it is going to be very difficult to find a lender that will allow you to put 15% down on an investment home in this environment, and again even if you do, you will pay a hefty fee in points.

As you become more experienced with this method, you will be able to identify potential deals in any market environment.

Tech is improving by the day and there will be a point where everything is so regulated no one will ever be able to get away with anything.

In addition to this, put yourself in any environment possible to be around a higher volume of RE transactions.  

@Jorge Pimienta Anytime you can negotiate a seller financing deal (especially with the higher interest rate environment we're in now), that's a win for you as it'll likely end up being a good deal cheaper and costing you less out of pocket, less documentation, etc.If that's not an option, and you plan to flip the property, then you should look into hard-money loans.