Running total widget

Hi all.

I’ve recently installed WordPress and I’m looking for a specific plugin. I’ve been searching for hours and can’t find anything.

What I’d like is a widget on the right that will simply allow me to add the cost of a certain item plus the name. At the bottom there’ll be a total amount spent.

Basically it’s to track the cost of my future education. I’d like it to be a running total of various tools and books I’ve needed to buy. Is there any widet like this out there already? Thanks!