Ladybird spiders, and the sexual dimorphism drives everything. Adult males are red or orange with black spots and genuinely resemble the insect they are named for. Females are large, black, and unremarkable.
European velvet spiders, small, burrowing, building a silk tube in soil with a sheet above it. Slow to mature, and males die within months of reaching that adult coloration.
That is the market distortion. The animal people want to buy is a short-lived terminal male, so the sensible purchase is a juvenile with a coin flip on sex, and pricing reflects that gamble. Sexed adult males carry a premium that makes very little sense on a per-month-of-life basis, and buyers pay it anyway.