premise: Anyway , initially he said he can give us a $ 50 cash return if we trade in our own vacuum cleaner . When I asked if that 's the lowest price he could give us , initially he said yes and when I asked again later , he said if we took the demo model , he could give us $ 100 off . He added that he could n't be bothered to pack and unpack the machines so he said he would just write " demo " in the receipt but in actual fact , we would have a brand new one . Why is the person offering a $ 100 discount ?
hypothesis: Because he really wants to get rid of the demo model .