Also, firecrackers are plentiful and cheap, but you can t take them onto the plane. Rare coins and antiques cannot legally be exported from most SE Asian countries. It is illegal to bring them home. Do not take fruit or vegetables from one country to another. TOP Postage and Phones . . .
People like to stop at the post office often.
Stamps with sticky stuff on the back are relatively new in SE Asia. In some places, you can only get stamps that you have to affix to your letters and post cards with glue from the glue pot. I suggest you bring a glue stick for this purpose. Postage stamps make great souvenirs and gifts. You can buy post cards from kids on the street everywhere.