Feature Request: Editing shipping costs for online store

[#1]

I want to edit the cost of shipping on my on-line store but can't seem to do so.  The cost of shipping comes up automically as a set minimum of $15.00.  I would like to lower this for an item I am selling that is relatively small and can fit it a brown envelope and I could ship within canada for $5.00.  How do I do this?