Toyota Repair: Toyota Camry check engine light came on., toyota camry, code numbers

Question
One week ago the check engine light came on. I have checked the gas cap but the light remains on. It is a 2000 Toyota with 115,000 miles and it runs great. I have checked all the fluids and lubricants.  All are fine and there are no leaks.  I have always changed the oil at 3,000 miles.  I called a repair shop and they said it would cost about $90.00 to check it out and could cost at least $600.00 if it is the catalytic converter.  They only suggested the converter as a possibility.  Can I continue to drive my car with the light on or is it really necessary to have it fixed.  Thank You

Answer
Most causes for check engine lights are emission control related and do not affect driveability but there are some reasons that are more serious, locate an Autozone, Kragen, O'Reilly or similar parts store they usually help you get the diagnosatic trouble codes at no charge, write the code numbers down and get back to me and I can help you with this .