[bottled_poe]

Sanity check... Let's say I'm particularly careless and so locating my keys costs me 2 hours per year more than it would without this device. (Assuming I can find my phone, which seems unlikely at this point). Also assume this product has a lifetime of 2 years. So it might save me 5-ish hours over the product lifetime. If I value my spare time at, say, $100 per hour, I should be willing to pay several hundred dollars for this product. There must be other factors I've ignored, but it seems plausibly worth $20 or more if it is actually good at what it claims to do.

[FussyZeus]

My wife is especially terrible with keys. This would save her way, way more than 2 hours per year.

I wouldn't need one myself but trust me, there are folks out there who would really benefit from it.

[devoply]

It's frustrating to lose your keys. Enough of an annoyance that you might pay for a fix. Then there are those who chronically have this problem, that's another market. People with memory problems, etc.

[pc86]

Well, your spare time is by definition worth $0. Nobody would otherwise be working during the time they're looking for keys. I think it's important to do this type of calculation for things at work or for side projects but you know how you can not lose your keys and not pay several hundred dollars for a fob? Put them in the same place every time.

Also the fact that you can buy something nearly identical for $1.40 pretty quickly rules out paying several hundred dollars for it.

[moomin]

If spare time is worth nothing why do people purchase additional holiday?

Also, the time spent looking for keys is often spent just before going to work, which makes you later for work than you would have otherwise been.