Web site sales histories?

[dag]

Is there a relatively easy (and preferably free) way to find a sales history for a given Web site? I know I could go through the DNJournal archives, but they don't seem to have an easy search function for that (other than Googling it), and it's not comprehensive. Any suggestions? Or is this really not something that's available? I realize this isn't as easy as real estate...but I thought it was worth asking...

Thanks!