Instead of Sam Sand Dunes, please check Khuri Desert. It's very much unexplored and non-commercial unlike Sam.
We were staying at Pal Rajah Resort at Khuri & was the best hospitality we've witnessed.
Hey,
Most places are budget stays in Sam Sand Dunes for a desert stay near Jaisalmer. The main road on the right is where a string of camps are put up. You can directly go there and book for a better price.
Hope this helps.