Slowly but surely, I'll be able to complete posting parts of typical construction of homes with a price breakdown so people would know how much do they need to prepare to build it.
This post should help you know the amount you need to construct a stand-alone single garage. Meaning, it is a different structure and is not a part of your actual house. Below is the 3D plan of the garage I've done estimates with.
As you can see, the structure in itself serves its purpose. That is to keep your car from the elements. There is no fascia and ceiling to lower down the cost. Building it with fascia is completely optional but I opted not to have it, since Filipinos are very budget-minded.
The garage construction cost breakdown is as follows:
Concreting Structure: Total =PhP 20,954.99
Footing = PhP 2,273.12
Column = PhP 4,750.28
Slab-on-Grade = PhP 9,555.83
Formworks = PhP 4,375.76
Roofing Works: Total = Php 23,995.14
Truss and Roof Sheets = PhP 23,995.14
Painting Works: Total = Php 4,008.19
Column = Php 809.02
Trusses = Php 3,199.17
Electrical Works (without wall lamps):
Wiring and Lighting = Php 2,211.30
Electrical Works (with wall lamps):
Wiring and Lighting = Php 6,072.15
With a total construction material cost of Php 51,169.62 without the wall lamps and Php 55,030.47 with the wall lamps. Again, that amount is for the materials only.
The labor rates is around 40%-60% of the materials cost (this is only a guide as labor rates vary per location). My estimate for the labor cost should be around Php 25,000.00 and they should be able to finish this in 2-4 weeks.
If there is a contractor / engineer / architect near you then I suggest you hire one. In fact, I would always suggest you to hire a professional. They'll know what you need.