I bought an adapter and a tank to carbonate my drinks. I go to a local beverage gas supplier to refill the tank.

https://www.rodsbooks.com/sodas/

I like the variety of snow cone flavors from https://www.snowballsupply.com/

Buy the concentrates, you save the most money.

I bought acesulfame potassium from here: https://prescribedforlife.com/products/acesulfame-potassium-ace-k-200x-sweeter-than-sugar-kosher-semi-natural-granular-sweetener-html