I make sturdier stuff (jewelry), so I don't need to do hugely protective packaging. I do, though, need to be sure that I'll get paid and not have than rescinded once they've gotten the goods.

I think it's completely fair to charge for the time and materials it takes to ship; whether one adds that to the item cost or to the shipping cost is a matter of preference.

Since for ME my shipping expenses are different if I'm sending within the USA or outside it, I tend to add at least some of the international shipping costs to the international shipping, rather than the cost of the items. But that's a personal choice.