Add number of fields to feature class with arcpy

addFields.py

import arcpy

fc = r'C:\folder\database.gdb\featureClass'

# fMax = number of fields that you need to create
# fNum = starting points
fMax = 300
fNum = 1

while fNum <= fMax:
    # Add a new field to the feature class until fMax is reached
    arcpy.AddField_management(fc, 'field_' + str(fNum), 'TEXT', None, None, 10)
    print fNum
    fNum = fNum + 1