As of May 18, I owned 403 Prismacolor pencils.
That means that Ophelia’s guess of 400 from the very first day was the closest one. Congratulations Ophelia — pick out a black and white dress (any of them, not just the most recent) and tell me how you want me to color it!
Thanks to everyone else for guessing! I’m sorry I made it go on so long, though…
Brian made this chart of what the votes looked like. Thanks dear!