Honestly I think it really depends on 1. where your buying it (ie. Craigslist, Kingsnake, or a reputable breeder) 2. The line of pastel (blonde pastel ect.)
I usually have seen males go for $50-$150 and females anywhere from $100-$250
Just my observation. I personally sold a male breeder pastel for $75 as I didn't need him anymore.