It turns out that you can use generic filament (like ours) instead of having to use official 3DSystems cartridges. This can save you quite a bit of money, and gives you the opportunity to experiment with colors that you can't get from 3DSystems.
Here's how to do it: Start the printing process with a full (non-empty) cartridge in the printer. After you have selected the file to print, but before actually starting the job, switch out the cartridge to an empty one. When the printer complains there is not enough filament, hit the check mark on the control panel to continue. The printer will then resume the print operation.
All that's left to do is to feed the generic filament into the feed tube for the print head. Now, you can use our 1.75 mm filament!
Read more: http://www.howmuchsnow.com/cube/
Also, be sure to check out Thingiverse for other designs.