The Nexus 7 is no longer available from the Google Store. The stock Android slate recently ran into some major trouble when both the OG and second-generation model received the update to Android 5.0. Some of those who tried to update the slate found themselves with an expensive paperweight after their Nexus 7 was bricked during the updating proicess.
The OG Nexus 7 has gone through 10 upgrade cycles after starting life with Android 4.1 and recently receiving Android 5.1. The original model featured a 7-inch screen with a resolution of 1280 x 800 for a pixel density of 216ppi. A quad-core 1.3GHz NVIDIA Tegra 3 CPU is under the hood with 1GB of RAM and 8GB of native storage inside. There is one camera on the unit, a 1.2MP front-facing snapper. A 4325mAh battery keeps the lights on.
The second-gen Nexus 7 also comes with a 7-inch screen, but on this model the resolution is an improved 1920 x 1200. The pixel density works out to a superior 323ppi (compared to the OG model). A quad-core 1.5GHz Snapdragon S4 Pro drives the tablet, which has an Adreno 320 GPU handling graphics. 2GB of RAM is inside along with 16/32MB of non-expandable memory. This unit offers a 5MP camera on back and a 1.2MP shooter up front. A 3950mAh battery powers the tablet.
If you've been hoping to purchase a Nexus 7 tablet, your best bet is to check out eBay or Amazon as you might be lucky enough to find some leftover inventory available.