It's easiest to use B&W film developer as one-shot. It's possible to re-use or replenish but that introduces complexity that I don't think you would want to get into right away.
You're only going to use a little of the stop bath so it will last a long time. Dump it out after use.
The fixer will last several rolls of film, but it has a definite capacity, once you exhaust it you will need to recycle it responsibly.
p.s. I work for Kodak but the opinions and positions I take are my own and not necessarily those of EKC.