General stores, like this one on the road between Luang Prabang and Vang Vieng in Laos, sell all of the vital ingredients of this country's cuisine in little plastic bags. It's kind of like a primitive version of the McCormick section at a western supermarket. Apart from herbs and spices commonly used in some other cuisines, such as chili, ginger, galangal, mint, lemongrass and tamarind, these simple roadside shacks offer up more exotic fixings endemic to Laos and Northern Thailand. Yanang leaf is used in the preparation of soups, cha-om (a kind of wattle/acacia) is thrown into soups, omelettes and curries, and padek is a unique freshwater fish sauce.
I recommend Manivan Larprom's blog if you're interested in learning how to do some Laos cooking at home. Most of her posts include instructional videos. She was responsible for solving the mystery of the backwater eggplant cremations not long ago.