There are some good exchange locations in Luang Prabang (next to the post office and the gold shop across from Dara Market are the ones I usually use). But there are also places that try to cheat people. I recently had such an experience at the exchange shop next to Dexter's restaurant. I was exchanging money for a group and the teller try to short me 500,000 Kip! So sad. I've had a few other similar experiences at other exchange locations in the night market area. If you are ever given a LOT of small bills (5,000, 10,000 and 20,000 notes), be careful.