I used to own a small business and did a lot of shipping. I, also,
found it best to just build the handling cost and shipping materials
into the item. But don't worry yourself sick about exact costs for each
item. Take an honest look at your overall materials costs and time and
then divide it by the number of items you can usually ship with that
amount of materials and time. My off hand guess would be that $2-$3 is
going to cover most small items and most people will not even notice
that small of a price increase.

Check your box and supply source, too. We found we could order things
like peanuts, bubble wrap and boxes from a wholesale paper distributor
far cheaper than you can get them from stores.

Earl