I'd say Nicki. Madonna gets let off considering this is her 12th studio album, while PF:RR is only Nicki's 2nd and she's supposed to be the 'IT' girl of the year so her sales are just dreadful when you look at it.
Madonna............she hasn't even been certified gold yet in the U.S, and her worldwide sales are a quarter of what Hard Candy did. Regardless of age, it's still a flop album lol
I don't get why people are saying Nicki is not a flop because she has a successful single and a decent selling album.
Madonna might have a decent selling album and no successful singles, but are you guys forgetting the fact that she's on massive tour right now? Yes her era is a flop too but it's way more successful than Nicki's.