Maybe 50 bucks if it was in better condition. As it stands 40 bucks seems more reasonable. Whoever buys it is probably gonna have to end up replacing the circle pad, and maybe the top screen too, so obviously it's going to be worth less.
I have an o3DS in near perfect condition, has had screen protectors on it since pretty much day 1 so the upper screen is in good condition as is the circle pad, even then I don't think I'd get more than 60 bucks for it considering 2DS consoles went for $80 brand new at one point, and besides the clamshell form factor and the 3D they are the same hardware.