Which Shipping Rule to Use Question

I have to make sure there is no shipping charge associated with any audio file which is represented as category id number 5 in the categories table

There are other products like books and videos which I have already configured with their associated shipping rules and those are workign great.

But now I need to create a "audio" shipping rule that charges no associated shipping for it

How could I acheive this?

http://www.missionariesofthepoor.org/music-details.php?id=4

it not a matter of creating a rule to apply no shipping to audio, it's a matter of setting the other rules to not apply to the audio category.

in your rules, you can use the Based on items with a specific column value option for the trigger and the calculation.

set the rules up so they apply to the other category values and not category 5, this way the audio category is not included in shipping.

Im not sure I understand, perhaps you could explain the steps?

Do I have to create one for each type?

another option is to set the weight of the audio items to 0 and and the weight of the other items to a real weight, then set the rules to calculate based on the weight.

you don't really give much in how the shipping should apply to the other items, so it's difficult to give exact specifics on how to set it up.