CollectionDB or TheCollection is a handy app if you collect any kind of items.
You can build your own database with a picture of each item and manage their details such as their price, date of purchase...
There are 2 types of data you will manage:
With each picture will be associated information such as value of the item on the picture, its description, date of purchase etc.
With each collection will be associated a list of pictures.
The pictures can be imported from the library or you can take them with you device's camera!
In fact TheCollection can be used for other things. A user said he used it as a Christmas shopping list, taking a picture of each item, and saving its serial number.
NOTE: Ipod Touch user's who don't have a 4th generation do not have a camera.