RE: Sales and Profit Software ?
I do not think you are going to find commercial software that is any simpler than quickbooks or quicken. I would suggest getting them and only using the featurs you want. I know people who use it for tracking expense in business exactly the way you want, basically you can go to the main page and enter money in and expense out and it will give you the profit.
The other thing you can do is explore the other features of the software, all the "crap" in these programs is there for a reason, it is amazingly useful for maintaining your finances. Start simple and then if you have some spare time just play around with the features. You will be amazed how that software can give you new insight into how you are spending your money and even how you are wasting your money. It is often hard to see small amounts of money getting wasted over time without something like this to track it, and as we all know a little bit here and there adds up rather quickly.
But if you really want super simple... make an excel spread sheet (or any other spreadsheet program) with three coloumns, one for what the item is, one for expenses and one for money in. At the end of the day or week sum up the expense and money in and then subtract expense from moeny in and you are all set. With the sum and math functions you will spend like 5 seconds crunching the numbers once you have entered the data.