carpet over rug - military housing

Hello, I live in military housing and they all have the same tan carpet everywhere. Maybe some of you are familiar with it. I have a carpet cleaner that works okay but am looking into some rugs to cover parts of it since we have little kids. I am looking for a fairly cheap rug that is soft so I can toss it if it gets too gross. Does anyone have suggestion for rugs/pads that will stay in place?