All flavors of Crush are caffine free :) I crave orange or cherry usually so thats what I get when I induldge. As long as you dont overdo it you are fine.
Look at the different brands out there, you may just find one that is caffeine free if that is what you are worried about. So long as you do not over indulge you should be fine!
You can also drink grape juice, or even half-and-half grape juice in sparkling water, if you crave the fizzys. It's better for you than grape soda, since it probably isn't jammed with added high-fructose corn syrup.
Grade soda is fine. Just watch out for all the sugar and don't over do it.
I even gave in to my diet coke craving once in a blue moon. As long as you still drink plenty of water and your doc is not against it due to any medical reason, you should be fine.
If you crave it, drink it lol. I've craved pop this entire pregnancy, which is bad. I would only take a couple sips of it, or just a half a cup. Sometimes even a whole can. Just don't drink it all day and night and make sure you drink lots of water to stay hydrated.