The problem is that most of the known suppliers are selling the Proxmark3 for around $420. I then found that Elechouse has their internal version of the Proxmark3 V2 for only $200 ($220 with a battery to make it truly portable).
Building it was fairly simple and Chris Merrett has an awesome github package put together to make installing it on OSX painless.
Once built and tested cloning HID Prox Cards (which open most corporate doors) is this easy:
I am really looking forward to getting this out into the wild and showing people why they shouldn’t trust their door locks at their business or in their hotel room.