Purple Cash
When you have purchased all the available demos for a particular craft item you can buy extras with the purple cash (a.k.a future bucks)
Forum Discussion
- Firstly, you need to craft all the demos of an item at the 3D printer. For example, the holo-tulips, you need to craft 12 of them. Once you craft all 12, you can't craft anymore with robot parts, so you have to use the purple cash a.k.a Future Bucks :D
