Fragrancenet is a legitimate site. As many sites do, they offer "tester" bottles of certain fragrances at great discounts. They aren't fancy. They usually have no box and frequently not even a top/cap. Maybe the one you're looking at is something like that. I wouldn't hesitate to buy it though, especially if it's very hard to find.
I don't know about international shipping, but within the U.S., it's free if the order is over $70. If it's under that amount, you pay shipping. Sometimes they send out "free shipping" codes, too. But you can only use one code per order. You can't combine codes for discounts off fragrances and free shipping codes.
I don't know why your 15% off coupon didn't work. Try this one and get 20% off. It's been a good code for nearly a month (that I know of). But you better hurry. It might only last one more day.