Expense Clam is an expense tracking app for Android which has features such as photographing receipts, data export, and automatic currency detection of whatever country you have just traveled to. There are two versions. Expense Clam is free if you are willing to put up with ads after 30 days, and if not, there's the paid version, which costs all of £1.70.
If this might be of use to you - and you have a device running Android* - they are both downloadable from the Android Marketplace.
* Unlike me at this point. Also, yes, the logo could use major improvement, but the rest of it looks pretty good, I think.
Edited to add: If only it were a different kind of shellfish, he could use something like this. But I don't have any Playmobil clams.