Okay guys patulong lang po.

I got this used EK hatchback and it was okay for few days and then suddenly upon starting up, some smoke came out from the hood. I didnt try to turn off the engine and after few minutes, the smoke disappeared and I was still able to run the car (Just tested around the neighborhood to see if it would break down). Car seems to be okay though except for the smoke everytime I start. Quite disturbing,

What could have been the cause of the problem? Can I have an estimate how much I would spend to have it repaired (worst case scenario price).
Advise would be appreciated. Thanks