It is unwise to declare commercial items as "gifts". Customs here an abroad are not completely stupid, you know. They may charge your customer import duty and VAT, and a penalty, or may confiscate the goods. In addition they may well in future examine (and delay) every packet which has your logo or sticker on.
I am often asked to under-declare the value of exported items, and I am not prepared to do so. Do you want to deal with a merchant who is blatently dishonest?
Buyers need to take up import duties and taxes with their government, not with you. Marking as gift is not a wise idea. Customs will catch on and blacklist your packages for scrutiny.
Best idea I've heard on getting through customs quickly is to put your sales invoice in a half sheet insert so the item price is clearly visible without opening the package. If the product is sold on feeBay including the description page showing the item price.