The slug rounds are 50 for $17, the balls are 100 for $13(183 grain).
here is an online video that i liked, i think i might just get one to use for
target practice in order to save money, but idk.
http://www.youtube.com/watch?v=ENsdA4Gel44
And here is one of a slightly less powerful one that is cool.
http://www.youtube.com/watch?v=c-hJYrR_-gw