You see an advertisement in newspaper about an apartment that the developer is selling at INR 2500 per square feet. The apartment's total advertised are is 1200 square feet. You immediately calculate the cost as 1200 * 2500 = 30 lakhs.
Wow, 30 lakhs is what you were looking for and is very well in your budget. You want to call the developer and book the flat as soon as possible.
But wait, this is NOT the actual cost of the apartment. There are many other un-advertised costs which are hidden and are added over and above the advertised price. And yes, do NOT make the mistake of underestimating these costs and they normally make upto 20% of the advertised cost. [More]