I have no idea of the cost for shipping an envelope or a small box, I see different vendors ask different amounts.
Postage rates are a real problem, I didn't start to sell my candles outside of italy just because of that, everytime I try to figure it out it costs a lot. But candles are heavy, seeds aren't.
Sometimes people are willing to pay to have something they can't find in their country. If there are no difficulties the choice could be let to them.
I buy almost all my candlemaking supplies in USA, it's a cost but I pay it happily because I can't find the same quality here.