Thoughts on the Cushion Lab?

I’m trying my hardest not to pay hundreds of dollars for a comfortable chair with lumbar support and I keep on getting adds for these cushions. They are a lot cheaper and would work on my existing chair that is still in good condition.

It seems really gimmicky but I’m wondering if anyone has any experience with them. Another option is that I’ve been seeing a ton of office chairs for sale on FB market (I’m thinking office foreclosures), like used aerons for $400-$500.