http://www.headphone.com/products/headphones/all-headphones/akg-k-24-p.php
The K24Ps are cheaper ($10 on Amazon), but they don't sound as good, and since they're an open design, they don't provide any passive noise attenuation and will let other people hear what you're listening to.
I just got the K26Ps, and I'm thoroughly impressed; they're a sizable improvement over my old Sennheiser PMX200s in all aspects. Better bass response, better overall resolution, more comfortable, and a better seal for blocking noise.