If you purchase big products in Thailand, such as electrical products, then you could be entitled to a VAT refund (Value Added Tax refund). This is like what a sales tax is in the states. But if you purchase gemstones, then you cannot get a refund on the VAT.
To claim a VAT refund, you must leave Thailand with the purchased items within 2 months after the date of purchase. Also, the business where you purchased the items need to have “VAT Refund for Tourists” advertised somewhere. It usually comes in logo form.
You cannot pay more than 2,000 Baht per item (with the VAT added too). In total, you cannot claim more than 5,000 Baht. You’ll find VAT refund counters at international departure terminals.
Never drink or rinse your mouth with Thai tap water. Always purchase bottled water instead. This is a safety precaution.