A new radiator for a vehicle costs between $80.00 to $300.00 and sometimes more depending on the make and model of vehicle.
If you can replace the radiator yourself then it would just be the cost of the radiator and your time to replace it.
If the radiator is easy to get out they are pretty easy to change and would likely take you 1 or 2 hours to remove the hoses, unbolt anything holding down the radiator and then install the new radiator.
You would have to drain down the coolant into a bucket and then put the coolant back in after you replace the radiator.
If you have an auto repair shop replace the radiator it could cost you $100.00 to $400.00 in labor charges plus the cost of the radiator.
The cost with parts and labor to replace a vehicles radiator is between $200.00 to $1,200.00 depending on make and model of vehicle.