CAN I VISIT THE GREAT WALL FROM GUANGZHOU? IF YES HOW MUCH CAN IT COST? HOW MANY KILOMETERS?

Of course, you can take that trip, but it will be a long journey.
The Great Wall is in Beijing and it is about 2300km from GZ. So it is hard to predict the cost, because it depends on which kind of transportation method do you choose. In general, the fee will be high.