Right about the time the film was opening the 8" figures at my local Target sold out and then got restocked. Those were the only Avatar toys that store had until the weekend of the film opening. Then they stocked the mech suit and Grinder and the Banshee/Direhorse/Thanator wave of mid-sized beasts. We don't have any of the 4" figures.
The local Walmart hadn't had any Avatar toys till I stopped in their Sunday night, I found 2 Scorpion Gunships in an aisle which had been Lego (but was sold out for Christmas). No figs or anything.
The TRU store I was in had the Gunship and a Direhorse but had both scales of figures. The 4" figures were nearly all Na'vi with the pilot, Trudy, and one Marine being the exception.
Target in Vestal, NY had the same vehicles/beasts as my store but they also had the 4" figures including both humans and Na'vi, but not a large selection. That's where I bought Neytiri.
Walmart in Vestal was where I saw the most figures. They had all the humans and the Avatar/Na'vi figures. They also had the mid-sized beasts, grinder/mech suit and both the Gunship and the Leonopteryx. Basically the whole line. That's the only store so far that I've seen carry everything.
As I said, I'd probably buy the whole line if the figs weren't so expensive. I have to get that Gunship open and see what the quality is on it.