I've had trouble finding it in NYC; my initial idea for doing SodaStream refills was to simply buy the appropriate weight of dry ice and fill the canister by unscrewing the top, but I wasn't able to find any dry ice available for purchase.
For those curious, I ended up finding a welding supply store that just sold pure CO2 in a tank.
For those curious, I ended up finding a welding supply store that just sold pure CO2 in a tank.