You can also teleport to any of the open world areas and buy them from the repair vendor (often doesn't actually say repair though)
You can get Bottled City Soder from: - Opening 15 Kryptonian Time Capsules - Time and Space vendor for 75 Quarks - Broker or other players since it's tradeable (if you are on Xbox I'll just give you one for free)
This right here, If you have the quarks to pick it up. You also need to level it up though and it takes a bit to get it to be as decent (healing wise) as the soder colas but it does offer buffs too eventually.
Anything tagged as "Repair Vendor" sells them. They drop naturally as rewards once you are past Level 30. If you stay in the House of Legends, the vendor will be hard to find (even I don't know where it is), but if you go to your Faction House (Hall of Doom, or Watchtower), in each of the wings, close to the R&D Station, there will be a vendor that sells them. Also, in every Safehouse (Police Stations for Heroes, Clubs for Villains) there will be, again, a vendor that sells them.