The core element here is the air popcorn popper. Mine is the Toastess TCP-713
, but there are many others that work as well. The key is to get one that has its air vents on the side of the main chamber and a solid bottom. There's more info about that here
If you're willing to trek through some thrift stores you might be able to find one of these for $5 or so. Otherwise, it's not too bad to get a new one for under $30.
I got the raw beans from Sweet Maria's
in Oakland. They offer lots of different beans for $6-$8 a pound. I'd recommend getting the sampler
which can get you 8 pounds for $40 or $5 each.
The last part you'll need is a couple of metal bowls or, even better, colanders.These will be used to catch the chaff and cool off the beans.