Very basic question.  I was wondering if someone could chime in on the best way to set up a data field for a product’s options (e.g. colors, sizes) that do not effect the price.  I know there’s CartThrob Price Modifiers, but these options really don’t modify the price at all for me, so I wasn’t sure if this using the
CartThrob price modifier was the way to go about doing this.  Should I just create the option with the standard EE “Select Dropdown” option?  Does that work?

Also, I have about 5 different types of products (e.g. shirts, jeans), some of which share the same all the options (e.g. colors, sizes, shapes), but some products which do not share all the options (e.g. just color, not sizes or shapes).  Is it best to create a channel per product type and create unique datafields that are pertinent for just that product type/channel, or is there a way to use the same datafields universally for all the product types and just pick and choose which datafields to use. 

Example. 
Product Type 1: Shirts (color and size options needed)
Product Type 2: Jacket (color, size, pocket color options needed)

You should use a price modifier field for your options. Price modifiers don’t need to modify the price if you don’t want them to. Just don’t add a value in the price field of your options and you will be able to select the options without affecting the price.

is there a way to use the same datafields universally for all the product types and just pick and choose which datafields to use.

In each product entry, only fill in the data for the options that are pertinent to that product. Then inside your add to cart form, you would need to only show the select menus for products that have options.