I really like to use scentiments.com. I don't know if they ship to Spain but you can always check it out anyway.
Testers are wonderful because they are much less expensive. They are the exact same, in terms of the fragrance. The box is plain and some come with no cap. That doesn't matter because you will still smell the same as you would if you bought the fancy box. Paying less is always a great experience!!
Rip-offs are the worst. I've never been caught in one yet but I'm still young. Just be careful. Ask around for advice on a site that you are not sure of. There is also a shopping guide in the discussion board with a list of sites. There are reviews on them if you want to check that out.