OP, I am from Greece.
I have purchased many items from US, and I have to tell you, that regarding custom fees, if the item is sent via USPS, until now I have never paid custom fees. When an item sent via USPS arrives here, it is handled by hellenic post. Hellenic post, has its own custom employees, and they usually don't charge such fees. I have only paid a 3 euro cost for each package (it is a fix cost for all the parcels outside EU). Even if she has to pay, custom fees if the item is handled by hellenic post are really low. The problem is when the package is sent with private courier companies. These companies charge excessive custom fees in EVERY parcel. They collaborate with people doing this job as free-lancers and not as employees of the state, and no one can control what they charge. In this case, you also pay money for other reasons, such as airport fees etc. Also, you have to go to the airport and do the procedure yourself (complete many documents), otherwise, the courier company does it on your behalf and charges you a lot.
I had an awful experience, buying an alexander wang rocco from aloharag, and paying another 220 dollars to get my bag!
For the record, I received recently a chloe bag (price 399 dollars) and I only paid the fix 3 euros.
Hope that helps.