So on a related note from yesterday, here’s an example of an expense sheet I use on Google Docs. It’s so important to keep your receipts so you can easily update this. (Make sure to keep your receipts as proof of purchase just in case you get audited.) Some accountants will ask for them also to cross check your records.
At the end of the month, the total is what I subtract from the total amount made during the month, and that’s how I figure out my profit. Any questions, please ask!