Pastels are VERY dependent on color. A really spectacular, clean yellow color at that size could easily ring in at $500 or 750 or even upwards for a female. And I might happily pay it if she really looks good, especially if I could see her in person to confirm it. But most pastels will have browned out at that size.
For a sub-adult normal girl I wouldn't pay more than $200. Spiders I really don't know--I don't pay close attention. But a young breeder boy shouldn't be worth THAT much more than a nice hatchling.