Options per item

Each item for sale can include various options.  For example, a digital print may come in three sizes, like so:

This can be done like so:

Add the varieties, you want.

Use the Advanced option (on the upper right) to view the CSV code for the varieties you just created.  This code, can be copied and pasted to create the varieties drop down for other products.  This can be quicker than creating the same varieties one-by-one for many products.