I've heard good things about water kefir.

Kombucha is fizzy and slightly sweet...maybe that would be a good option? I love it. It has something like 4 g sugar in a bottle. But it tastes like it has so much more.

I like GTS Gingerade.

Take a dash or two of fresh-squeezed OJ and mix it with seltzer water. Refreshing, sweet, and usually does the job. I know I've had to do it occasionally when I'm bartending and just need something like that. Anyway, not the SAME, but it might help.

Definitely look into water kefir. I bought some, and now it's replicating at an astonishing rate. It basically makes a lightly carbonated probiotic drink, and you can flavor as you see fit. Current favorite is with 1-2 oz of pineapple juice, a squeeze of lime and a sprig of mint. Like a cocktail!

Also, you can look into the flavored carbonated water--I like Trader Joe's berry flavor (no sweetener, just berry flavoring).

That said, I still haven't kicked my diet coke habit, so you know what they say about people in glass houses...

Try seltzer instead. They were my saving grace when I was trying to kick the diet soda habit. If you are having trouble not drinking juice, a good way to wean yourself off of it would be to start diluting it with water. For example, fill 2/3 of your glass with 100% (no sugar added!) juice, and fill the rest with water...once you get used to that, only fill it half way with juice and half with water and so on and so forth till all you need is a glass of water with some fresh lemon, fresh orange, fresh cucumber, etc. etc. mixed in.

Um. 100% juice that is fresh squeezed by hand is paleo- it's just not very healthy.

La Croix, coconut flavor is delicious. Carbonated water and flavor.

I greatly enjoy - seltzer/soda water, take a half a lime and squeeze it into the soda water. It's quite enjoyable, and I really like that bite you get when you drink the soda water fast.

My partner didn't kick his coke-zero habit for about 10-12 months after going paleo - we got a Soda-Stream, and he used their version of coke-zero, and added less & less of the syrup over a period of time, and finally, he stopped after he'd been drinking 1/2 to 1/3 strength sodas for a few months, and had reduced the volume to just one glass with dinner. Up to that point, just missing a 'dose' would have given him a migraine. When he did finally stop, he didn't have any issues.

Now he drinks water only as his main beverage. He doesn't now, and has never drank, coffee or tea. He recently found that he really likes plain black tea Kombucha. The brand we like is Invisible Alchemy, and only the plain one. But this is limited to one 4 oz dose a day - nothing like the liters he drank of Coke Zero.

Try some kombucha. It is a effervescent fermented tea drink with many flavors. Pretty tasty substitute for soda. I have had a soda in over 2 years, so my recollection may be fuzzy, but these are good.

Get some club soda or seltzer, then put in 8 drops of "sweet leaf" stevia in Vanilla Bean or Lemon Drop flavors. Tastes AWESOME... in fact I'm going to have a zero-carb, herb-flavored cream soda RIGHT NOW...