This paper presents a dynamic model of heterogeneous beliefs (where investors agree to disagree) to study the positive price-volume correlation during a housing downturn. It shows: (i) beliefs may diverge, which prevents some pessimists from buying; (ii) in the case that beliefs cross (i.e., buyers become more optimistic than the sellers), home sales occur but are delayed due to the buyers' option to sell cash higher (using house as numeraire) if the downturn worsens. Such option to wait also has implications for the velocity of money during deflation, troubled assets since 2007, takeover bids, IPO waves, and fire sales.