There are plenty shops in Murghab, which are only to find in asking local people. Those, however, only offer not very useful groceries for travellers. Nearly everyone is baking their own bread, so you need to ask around for someone who sells their bread.
Although Murghab has a few guest houses, there are no reason to stay longer then one night - there is simply not much to do.
About 10 km after the police checkpoint is a nice, wind still camp spot on a small river.