You may not think about this much, but the average cost of a scale for someone in a wheelchair to use is $1200 USD. While you can find some online for $500, the commercial units typically cost $1800 or more.
The current scale designed are a one-size fits all which means they can capture any wheelchair, manual and powered. However, this requirement circumvents the need of a particular segment who use manual chairs and can benefit from having a lightweight and more affordable scale designed for the home.
These all steel or aluminum scales weigh 60lbs or more making them quite difficult for someone in a wheelchair to manage or maneuver on their own.