To find out how much your Rolex is worth it would be a good idea to take it to a local jewelry shop to have it appraised or you can look online to find your special type and year of the watch. Remember to ask yourself if you indeed have a real Rolex because there are many out there that look real but are fake. You can find more information here: http://www.timeandgems.com/
If the "Rolex" was purchased on a city street by a man in an overcoat, it is most likely not worth what you paid for it. However, if you have or suspect to have, a real Rolex, you can take the watch to a jeweler or appraisal store to have the watch valued.