At tourist shops it's expensive; look for it in crammed little markets instead. It has a pleasant flavor and an aroma that will remind you of the wild Greek hillsides. Break a few sticks into 8 oz of water, bring to a boil and then simmer until it is a honey-gold color. Drink plain or with honey.
Some Greek grocery stores even offer it in inexpensive tea bag form - while I prefer the whole sticks of the herb, the tea bags will do in a pinch and they are easy to transport.