[Fradow]

Depending on how it's broken, sometime you'll be able to glue plastic parts together (it was recommended to me to use the gel super-glue, not the regular one).

Another interesting material is two part epoxy (like JB Weld). You can even make small parts out of it, for example redo a broken clip on a bigger plastic piece.

Due to owning and repairing a 20yo car with lots of brittle plastics, I've had to expand my plastic-repair skillset, and it's way deeper than you'd initially assume.