There's a steep entry fee when you can see most of the temple from the outside. Suggest saving the money, walk around, and instead check out the giant golden reclining Buddha in the neighboring Wat.
Very nice area to visit, between the temples and the golden stupa. It' indeed the most important national monument in Laos and the nation symbol. Be aware that the stupa has been under renovation
MUST VISIT: Arguably one of the best Buddhist temples in Southeast Asia. Make sure to visit the adjacent temples, including Wat That Luang Tai and its giant reclining Buddha.