That's hard to say right now... I alked to a wholesaler who said they will be in short supply at first. My guess is Toys R Us will have them... We won't know who else until mid-August.
Cool! It looks like the vpet trend is coming back!
Like Mothra said, don't be afraid to buy stuff online. I got mine from Iwantitcheaper.com. Mine cost £14.99* with free shipping to anywhere in the UK. I'm sure you will find something similar in the US.
*-(yeah, I know I could have gotten the Japanese version cheaper. Indeed, I hope to get one one day, but mam would have a fit if she saw me buying more tamagotchis! For some reason, she dissaproves of my little hobby. Besides, British stuff are always expensive! )