There are plenty of lodging styles in Vang Vieng, though only a few have decent views. One of the better economy options is the Saysong guest house, which has a great location right in the market, with a balcony overlooking the river with karst mountains on the horizon.
Decent fan cooled rooms are US$3 ( March, 2004 pricing). You may want to bring a lock to use with the hasp already on the door to supplement the somewhat lax security offered by the hotel's own door lock
Here are some pictures of the guest house. A view of a room.
The ensuite bathroom with western style toilet
The hotel lobby with the town market immediately outside
A view from the guest house balcony, across the river with the karst hills in the background
SaySong Guest House
+856 23 511130