This is a video of every R2-D2 beep, boop and bop in Star Wars: A New Hope. The total of 880 includes each individual sound he makes, so they add up quickly when he's saying something long. Although I actually watched the movie over the weekend to celebrate May the Fourth and I counted way fewer. I'm also a bad counter. "You were also watching The Big Lebowski." Valid point.
Keep going for the video.
Thanks to carey and K Diddie, who agree R2 has a surprisingly dirty mouth.