Duty Free shopping was once a huge attraction for travelers but in Thailand, I have great reservations about the prices you pay for most things. There are a few duty-free shops in town where goods can be pre-ordered and then picked up at the airport - you have to show your passport and airline ticket in order to make a purchase. I don’t think it is really worth it unless you are particularly short of time.
Many of the larger and more specialized shops now offer shipping abroad, and they will sort out the necessary documents and permits for this. Insurance should also be included. If you don't feel comfortable with this, there are specialized companies that will do it and sort out the arrangements for a fee. The GPO also has a parcel-wrapping service, and smaller items can be mailed from here. Another option is to go to the Thai Airways office on 485 Silom Road and, for a fee, they will ship them and sort out the documentation for you.
King Power Complex is Bangkok’s newest one stop service for tourists. The huge complex offers an amazing downtown duty free shopping experience. The building also has a sumptuous Thai restaurant, is about to open a spectacular theatre, and later this year will add a contemporary city hotel. It is situated on Sri Ayudhaya-Rangnam Road, Bangkok. Phone: 2677 8899.
Suvarnabhumi Airport features a lot of duty free shopping opportunities. While there is a wide selection of the standard duty free items - liquor, cigarettes, and perfume - there isn't much depth or variety. Don't expect a good selection of wines or liqueurs. You'll also find a lot of other kinds of goods, such as electronics, watches, books, and luggage. There's also a selection of way over-priced Thai products.
Dominating Bangkok's new Suvarnabhumi Airport duty free shopping is the aforementioned King Power group who have acres of space, quite literally. Duty-free prices at Bangkok airport in my experience are not great. With the Thai baht climbing against most other currencies and particularly against the US dollar (exchange rate roughly US$1=Bt34) a one litre bottle of Johnnie Walker Black Label costs about US$30 compared with US$26 or less at some other airports.
While this is not quite the same as duty-free, you can claim a VAT refund from most of the major stores in town. To be eligible, you'll need a total shopping bill of at least Bt5,000 so give that credit card some serious exercise. The PP10 form requires your passport number (though you may not be asked to actually produce it), and your departure flight number. Once that's all neatly entered, sign, and off you go. But don’t pack goods in your check-in luggage.
Jewellery, watches, and gold purchases over Bt10,000 need to be inspected and other purchases may be checked at the airport. After immigration head for the VAT refund counter and present your credentials to get some cash in hand for that much-needed snack and coffee.