Answer: waterbeds

AnswerCrossword Clue
WATERBEDSRest areas
WATERBEDSPeople use them only when they're full
WATERBEDSLiquid assets of a sort
WATERBEDSThey make waves when people toss and turn
waterbedsWATERBED, a bed filled with water
waterbedsA bed with a water-filled rubber or plastic mattress