maytime2
My daughter only buys "cheap" duvets from such places as B&M or Home Bargains. Especially when the children were younger and were more likely to be sick or wet the bed. Her reasoning is that it would cost more to take a duvet to a launderette to be washed and dried than it would to purchase a new cheap one.
I should add that the old duvets are taken to a dog rescue center to be re-used.
My sister has approximately a million grandchildren, so is used to bedtime accidents. She was saying that her local garage has installed huge washers and dryers on the forecourt, and others in the chain are doing the same. Her local one charges £15 to wash a (very large) load, plus the cost of drying, which is usually more than the washing charge. Unless you are running an B&B or something (so you use the machines to capacity), it would almost certainly be cheaper to donate soiled duvets than to wash them on anything like a regular basis. This is why I am so enamoured of coverless duvets, as they go in a regular machine and dry in no time.