There are a variety of price ranges. I have an Elecom HUGE which I think was like $80 (I got an Amazon Warehouse deal so I only paid $30), but there are a lot of different models across various brands.
Kensington is also a common (and more expensive) brand from what I’ve read online. But I encourage you to do your research, figure out your grip style, watch and read reviews, or see if you can try one in-person before buying.
Some companies make better products than others and some models are known for being lower quality even from bigger brands, so be aware of that. For example, Elecom uses synthetic ruby bearings instead of synthetic cubic zirconia bearings, so they wear out slower but sometimes feel scratchy (not really a big deal since bearings are consumables, but something to factor into the price and overall build quality).
I dunno, I like mine; it makes gaming easier and my mouse hand hurts less now so I do like to advocate for trackballs when they’re mentioned.
Okay, that’s your choice. I think it’s worth it but everyone has different needs. Enjoy the new mouse when you get one.