"Do you see that stapler? Convince me to buy it."
This is a test to see if you are an experienced salesperson. I do not have much sales experience but I would answer this question by thinking of salesman I encountered in the past that I felt was good. Think about your experience with sales people and list what they did. For example, they probably follow a format. First, they explain what the product is. Then they tell you the functionalities and where you can use it. Third, they should tell you how much easier it will make your work. Fourth, it should have a good warranty. The question didn't give you details. So feel free to make something up. It will show your creativity. Continuing, the product should have a good return policy. Finally, you can talk about the reduced price, or the price guarantee.
Short Answers
"This stapler is the newest model with easier to use features such as quick loading and safety protection. It also comes with a money back guarantee for any reason if you are not satisfied."
"This stapler is on sale for 30% off. The manufacturer is a new company so their prices are great right now. They have a great warranty program and it will save your company a lot of money with the substantial discount."
"This stapler has the best value. With a 15% lower sticker price, it provides identical functionality with the more expensive brands. It's durable and staples through more paper than the other brands."
Long Answer
"We are proud to carry this stapler. It's very durable and easy to use. Loading the staples is as simple as clicking this button on the bottom to open the top. The design is made with more curves to make it more appealing on the desk. It also is designed with more safety in mind. If you accidentally drop the staple on your foot or hit it with your hand, the curves are smooth enough where it will not break the skin. The warranty on the stapler is great too. It comes with a five year guarantee. We are currently offering this stapler for a low price of $19.99, and we have a low price guarantee. If you find a lower price in the next thirty days, we will gladly pay you the difference."
If you are applying for a sales position, you have to be ready to be able to sell anything in the room. I would recommend thinking about an outline. Get that in your head. Then use the outline to practice selling variety of things. You can use my answer as an outline covering features, functionality, safety, design, warranty, and price. But don't limit it to just these, if you have another idea, add it to this, or make up your own.