I usually feel out of luck when choosing an hotel in Savannakhet as I have never found one of these 80,000 Kips, cheap and clean GH that you can find in most provincial town. I can recommend you the New Saen Sabai Hotel. It is located in front of the ferry terminal, on the Mekong banks. Rooms are not very well designed but it does look new and clean and the location is really great. They have a promotional (opening?!) rate of 208,000 Kips per night, excluding BF. Wifi was not working when I stayed there but you can use of of the two connected PC in the lobby.