They have much cheaper ones, especially for teachers to use in class, even just a regular class, with kids who don't have sensory issues. My daughter has some, a few neat ones too. None of hers cost $75 though, not even close to that. They are fun to play with and can help you concentrate or work out anxiety just playing with them. I use my daughters' a lot. H even uses one of hers, composed of small metal cubes that you can fold into various shapes, of course making it a large cube. He fiddles with it all the time, when he's trying to come up with lesson plans, or a to-do list, thoughts on a project. That fidget has pretty much become his. So I think even when anxious or just thinking, they can help.

Though if you are at home and want something to fidget with, clay or play-doh works too. Some of them are as simple as stress balls (though for kids, they will make them fun shapes). You can even make your own stress balls with balloons and flour; there are instructions online.

Sometimes they sell variety kits with different types of fidgets, and of course, there is the all popular fidget spinner. My daughter likes them a lot in the car because she can feel & play around with them without looking at them as she is extremely prone to motion sickness. It helps her pass time on long drives, especially when the road noise is too loud to really talk (and she's got a pretty soft-picked voice unless yelling or screaming in anger).