* A [https://www.amazon.com/MakerFocus-18650-Battery-Shield-Raspberry-Arduino/dp/B07PS7DT62 similar commercial product] is about $8 US.
* Printing this design, as opposed to buying from Amazon, yields 580% savings
However - I think it is more appropriate to compare the cost of the above design with what most consumers would be doing, buying and throwing away Alkaline AA cells. a [https://www.amazon.com/AmazonBasics-Performance-Alkaline-Batteries-Count/dp/B00MNV8E0C/ 48-pack of AA cells] can be purchased for $14 US, yielding a per-cell price of $0.29. Assuming 2 AA batteries would need to be replaced in a device each year, this design pays for itself in just over 2 years time. If an environmental cost is factored into the production/disposal of Alkaline AA's, the payoff time is shorter.