The near perfect grade pins may have a small mark or an imperfection in the enamel. No pins with large cracks are being sold.
Unlike stickers, these cannot ship as letters so international shipping is a flat rate of $10 with includes tracking and is a discounted rate from what the postal service charges. The shipping fee does not increase if you add multiple items to your cart. It is possible you will be charged a customs fee from your country's postal service, but unlikely as that usually applies to things like large posters and plushies in my experience.
Shipping within the US should be somewhere around 2-$5 depending on where you are and the service you select.