This is a great tip. The disc is pretty cheap and you get Super and Super Turbo on one disc to satiate your SF2 needs and a second disc containing Zero 2 Dash. Which is a version of Zero/Alpha 2 with a few more characters and a few other things changed around.
And if you want to complete your SF2 collection on the Saturn, then get Capcom Generation 5 which contains SF2: The World Warrior, SF2': Champion Edition and SF2' Turbo: Hyper Fighting.
Also, a note about shoot-em-ups. Not all of them are expensive. I got Layer Section and Donpachi for pretty cheap and they are excellent excellent games.