Devil's Canyon will ship on June 25th, exact retail pricing isn't available but the bulk OEM cost for the Core i7-4790K is $339 while the i5-4690K is quoted at $242.
On top of this, Intel also revealed the Pentium G3258. This Anniversary Edition chip has a bulk OEM pricing of $72, it's a dual-core model with a frequency of 3.2GHz and unlocked multiplier. In terms of oldskool overclocking fun this could be one of the best chips Intel launched in quite along time. The only downside is that you'll probably still need an expensive Z-series motherboard in order to unlock all overclocking capabilities.