Idea Purchase

Engineering Area
Assessment & evaluation
Group or Individual
Amount of People
Type of Class
Duration of Activity
Half an hour or less
Type of Activity
Collaborative team setting, On-line Classroom activity


What is this technique about

The “Idea Purchase” method, also called the $100-Test, aims to find out which ideas the participants would be willing to give their own money for. Sticking dots to evaluate ideas is considered a democratic assessment of ideas (Dot Voting). However, when it comes to deciding whether I personally would spend money on the idea, as in the “Idea Purchase”, the decision is often more difficult. Asking participants to think about which idea they would really reach into their pockets and give away a hundred dollars for attracts attention and encourages participants to evaluate carefully. Focusing on the money can also help to determine whether the idea can be turned into a profitable business. 

Where does it come from 

The “Idea Purchase” or “$100-Test” method is often used in marketing and product development to test the viability of a new product or idea before investing a significant amount of time and resources in it. The basic idea behind the $100 dollar test is to approach potential customers or users and offer to sell them the product or idea for $100 (or a similar amount). If the majority of people are willing to pay for it, then it is a good indication that the idea has potential and is worth pursuing further. If not, then it may be better to go back to the drawing board and come up with a different idea.

The origin of the $100 test is not entirely clear, as it is a relatively simple and straightforward method that can be used in a variety of contexts. However, it is commonly associated with the Lean Startup methodology, which emphasizes rapid experimentation and iterative product development (Ries, 2011).

For which purposes it is used (why in your engineering teaching)

The “Idea Purchase” method is a quick and fun way to evaluate ideas in different maturity levels for new products, services or solutions.

How to use it

Once the participants have presented their ideas and solutions, imitation $100 bills are handed out to them. They are then instructed to allocate their 100 Dollars to a single idea and justify their decision. Subsequently, the ideas are assessed based on the query: “What is the value of each idea?”

Apart from individually, the “Idea Purchase” can also be used as a group exercise. Simply let the group decide how to spend the Hundred Dollars. This will probably result in a shortlist with fewer ideas (than the one created by individuals), yet will also require a team that is perfectly capable of working together.

How to implement this techniques online

Preparation, what do before the session
    1. Ensure, that there is a visible presentation of the existing ideas.
    2. Prepare imitation $100 bills on a digital whiteboard.
    3. Make as much copies of the $100 bill as participants or groups.

During application, i.e., while giving the session

    1. Explain the method.
    2. Assign one $100 bill to one participant.
    3. Ask the participants or groups to spend their $100 on one idea.
    4. Let them explain their descision.
    5. Evaluate the ideas. Which idea is worth the money?

Follow-up, about what to do after the session

    1. Identify the ideas that are further developed.

Examples and/or testimonials

Tools needed

You will need a platform to share screens and communicate with the participants, such as: MS Teams, Zoom or similar.

You will also need a white board solution with digital sticky dots such as Miro or Mural:

    • Zoom
    • MS Teams
    • Miro
    • Mural
    • Timer (phone, watch, computer)



NNgroup. (2017, June 23). How to Prioritize Ideas from UX Brainstorming Sessions. [Video]. YouTube. Available at:


Ries, Eric (2011): The Lean Startup: How Today’s Entrepreneurs Use Continuous Innovation to Create Radically Successful Businesses. ISBN: 9780307887894

Bland, D., Oderwalder, A. (2019): Testing Business Ideas: A Field Guide for Rapid Experimentation. Wiley, ISBN: 1119551447