Helped a friend with a college video project that used a lot of green screen (chroma Key) effects, and assuming you're not trying to get Billy Mays type quality infomercial, a mid level HD camera, a green backdrop, and Final Cut Pro would do you just fine. Maybe some lighting equipment. Look around, you can probably find a place to rent the equipment from.
He had a graphics art friend do the final editing, and you can probably hire a college student to do that for a few hundred if you're not proficient in it yourself.