Like stated below, check the fan scraping the shroud, or the radiator itself, if not that, check the pulleys off of your accessories, the bearings can go out and give you the same problem. I really need more information to try a diagnosis, I hope that this helps you! If not, then take it to a mechanic.
Bring your car to a mechanic even if you don't have money to get it fixed just ask them can they tell you whats wrong with it and give you a quote???
Sometimes the fan shroud touches the fan and this can make that sound .Check it out.