Via the internet (the cheaper method): http://www.1800contacts.com/
They do not require contact/a faxed script from your optometrist for APO orders. I looked around for a coupon online and found one for free shipping, which also saved me a few dollars. (google: “1800contacts coupon codes”)
Local: Pearle in Sittard (recommended by more than one person)
They are in the main shopping area, not far from the square. They are very courteous and good with children. While not cheap, they do accept the VAT form and have always been prompt and professional.