Has anyone sourced colored pencils ?

Hey everyone! I have set up a therapy center and need colored pencils for our clients. I am working on a budget and found some affordable options on Alibaba, but I am feeling a little overwhelmed by the number of suppliers available.

For those of you who have done this before, what should I look out for? How do you verify pigment quality and wood casing without ordering samples from every supplier? Any red flags to avoid or trusted criteria to filter by?

Any advice from someone who has been through this would be hugely appreciated. Thanks in advance!