Stylized Facts: Price Dispersion I'm looking for as many empirical "stylized facts" about price dispersion (in products markets) in the idea of Burdett and Judd (1983) as possible. 

For example, 


how high is the variance of price dispersion over different markets? 
Is there a time trend in price dispersion?
How does price dispersion vary over the business cycle?


For the last question, I only found Cornia et al (2011), who show that it is very pro-cyclical for airlines - probably not the most generalizable result.
A little empirical evidence for your first point can be found in


Erik Brynjolfsson &amp; Michael D. Smith (2000): "Frictionless Commerce?
A Comparison of Internet and Conventional Retailers", Management
Science, 46(4), 563–585.


They look at the markets for books and for CDs both online and offline and estimate the price distributions. Whilst they look at price changes, they do not present data on the change in price distributions over time.