I set up a simple sum formula for each group of categories, and one for the totals. If you need more lines, just click on the button at the left of the line BELOW where you want to new line to be, right-click and choose "insert". The formulae automatically update to include the new rows.
Since I posted this, I've added another column for check-boxes by each item.
The great thing about this kind of list is it's easy to modify, you can tailor it to your specific needs with very little effort.
As far as using that particular web-hosting site, I realize it's not ideal and if anyone has any suggestion for a better free hosting service, I'm all ears!