You would typically only need the motor block and maybe a drive assembly.  The motor is 9010.015 and costs about $110.  The full pump is about $200, part 9010.040.  Note that this pump has been replaced by 9011.040 which would fit in your skimmer and is cheaper, about $180.  I am out of stock on the 9010.040 and the new 9011.040 have not come in yet as a spare part, we should get them in a week or two.  You can order and get exact pricing on Tunze.com.