any raspberry pi2, power supply, and sd card (class 10) will work. You can shop around and look all you want, but I don't know where you live. Also, pretty much any of the kits will do. If you are referring to the hardware such as speaker/mic, then there are a lot of options. I use a logitech C170, but I have also used the internal mic on my laptop, and other things. That is part of the fun, try stuff and let us know what works for you.
Eventually we may get an "Approved Hardware List" together, but that will be some time. Since that landscape is always changing.
Sincerely,
Matthew Curry