Cut-and-paste from the rulebook, Page 60, second column:
Training Package Cost: Training Packages are purchased at a 25% discount. The cost of the skills in a Training Package depends on a character’s favored and nonfavored categories. Total the cost for the entire Training Package and then apply the discount to get the final cost of the package. So a Training Package with a total cost of 20 points would have a final cost of 15 points.