What is an easy way for managing the amount of products sold and money made? (For hair salons)?

Do you know what I mean. Like you put the stuff on disply, but is there an easy way of managing what is being sold, made etc.What is an easy way for managing the amount of products sold and money made? (For hair salons)?
Sure. Make a chart of products, and mark off what is sold, as it's purchased by each customer. Put the chart in a notebook or on a clipboard and have it near the register. You can also do a chart for money received for services, or just mark it down in a little planner book. You know, the kind of planner that has appointment listings pre-printed in there. Each week, add it all up, and you'll already know what you need to get from the beauty supply house, to replace the items purchased the previous week.