The prices on these have steady increased over the past year or two.
While the MSRP has been $80, I've never seen it being sold for over $45.
When these came out originally, you could buy them for $20-25, but they've been gaining popularity and demand and the price has gone up significantly.
You can still wait. As I posted a few pages back, the Superlux HD668B and the Samson SR850 are almost identical, with the Superlux being the OEM for both. They've come on sale at around the $25 range last year, though lately they've been hovering at the $30-35 range (shipped).