For a beginner, cycling has to be one of the easiest and cheapest sports to get into, because we really don't need anything special.

I recommend having the ability to repair a flat on the road. Tube, patches, pump, tire lever and a seat bag to carry them. That's really it for a beginning cyclist.

Sneakers and platforms are fine, basically forever. At some point, some cyclists decide that they want retention (clipless or clips) but it's perfectly safe to kick that can down the road, and the brutal fact is that you aren't losing much (if any) efficiency with platforms regardless of what people say. It keeps your feet on the pedals, particularly in a hard sprint.

Anyone can work out what clothes to wear. I'd get a water bottle, but objectively bottled water from the store works just as well.

For electronics, I'm a believer in knowing what the speed is - otherwise we tend to fool ourselves. For a speedometer, the cheapest wired Bell computer from Walmart works as well as a Garmin.

If you're looking for equipment to jump right in with both feet as an enthusiast, that's a different story.