300T can finish a 12-30sqm house if you do everything:
1. You make a design with the cheapest material possible.
2. You do the plans. Walay building permitay (pero you'll have problem on this in the future esp. on electricity..pero ok rani if sa probinsya ka).
3. You do the buying & coordinating on materials transportation.
4. You supervise all the works all the time.
5. Hire 2-3 people nga relative ra to help you. Meaning, you yourself is also a laborer. So make sure you have the tools as well.