$20 for a nice one is the most I've seen one go for, but that was a long time ago. I haven't seen many Snapchats for sale recently, but $100 seems ridiculous. Maybe $40-$50 would you get you something amazing.
Let's be honest your not up to any girls in your school an saying snap chat me Penis. It's more of a score thing for ransoms. If your just looking for a nice alias prob 60$
I paid $90.00 for "penis", but that's only because I had a buyer lined up for $140.00. The Snapchat "fire" sold for $35.00 on HackForums yesterday. So, I guess the price is really only what someone would be willing to pay.