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"Sale price: $199.99 (You save 26%)".. Now if you don't buy it you save $199.99 ..! :-)
Marketdroids, designers etc.. I think any engineer can smell the scheme of selling products for a price they are simple not worth. Or even outright useless.
Personally a hepa filter is useful. And in particular robot vacuum cleaners at low price would be useful. Ordinary manual vacuum cleaners feels kind of outdated..