Good evening dear Brother.
First bear in mind that at the end the acctual cost will not be what you thought, Once you will start construction you will be astonished how money goes,
Let's get to the point of Basement construction, first of all if you are living in well planned area you will be forced to construct basment walls plus floor with Concrete and steel and that will be minimum 9" width to avoid seepage and make the home durable and these days prices of steel, cement, Crush are sky high.
You will be required to Install additional lines of water supply and waste for basment plus a septic tank and water pump separately for basment.
Therefore you will be paying more money in basment rather than Ground F and First Floor.
Let me know if you need any information