Joe starts a lemonade stand
One morning little Joe decides to start a lemonade stand. He pulls out a table from his home, a label saying $1.50 and puts a big jar of lemonade on it.
Little Joe sells 20 cups of lemonade on that day. Overall he sells lemonade worth $30.
If this was a business, little Joe would have daily revenues $30.
This is revenue — all the money a business makes in a year.