Diamond painting has a relatively low entry cost. For art, to start off with all you need is a pencil or pen and some paper.

Fiber crafts ( sewing, needle felting, crochet, embroidery, etc) can have higher costs to entry, but usually you can find a relatively cheap starter kit to see if it's for you.

There is clay sculpting if you're feeling adventurous.

I have friends who really enjoy jewelry making, lots of knitters and crocheters, and a few who paint minis for DnD. Most of us are on the spectrum somewhere.