Here's my idea for a retainer app, Square.

I would like to have an app where I can:

-See how my items are being sold on my retainers on my phone.
-View my remaining time of my retainers 'venture', possibly reward as well or not.
-Would like to see how my retainers look like
-Would like to see the items the retainers are holding

I wouldn't mind paying an extra $1 a month for this feature with a two-step authentication step for every use.