By new Chromecasts, I assume you mean the 2nd generation, right? As opposed to new/refurbished.
If you're a Costco member, you can get two for $69 (which is essentially retail price), but this doesn't include the $6 Google Play credit that comes with each one: Google Chromecast HDMI Streaming Media Player 2-pack Bundle with $12 Google Play Credit. I also heard that they will be further discounted for Black Friday at Costco (but of course, they'll probably be discounted everywhere for that day).