We are also currently testing iCloud support for collections as well, which means collections data input using your iPhone will be synched seamlessly with your iPad or Mac, and vice versa. This will be a big step up from using Dropbox, which requires manual synchronization.
We do plan to charge a nominal fee (i.e. in-app purchase) to enable collections on the iPhone and iPad to fund future development, including features like collections statistics (i.e. how much is my total collection worth).
Lastly, we are looking for more users who would be interested in testing collections synchronization with their iPhone, iPad and Mac. Anyone interested can register their devices at http://tflig.ht/q1MRTs and drop me an email at [email protected]. We are especially interested in Mac testers who have existing collections that they would like to see on their iPhone or iPad.