60 products with 350 characters = 60 words = 3600 words
300 words for each category – 14 categories = 4200 words
300 words - very general at the end of each article (goes in all categories products) – has to be written one time
3600+4200+300=8100 words totally.
Please be advised that you bid for this amount of words. The words can be distributed for writing more products or less categories but at the end you will have to write 8100 words and therefore bid the price for words amount.