That is true indeed, but there's a cost for having your instance, proper cases, cooling the instances down, securing them, ensuring proper networking and more, pretty much the same stuff as a regular cloud, that's why I was wondering if people would be interested.

For the yes part, what would be the monthly price you'd be willing to pay?

You're right, all these aspects are important. If you add all these costs, such as electricty cost (3W * 24hr * 31day / 1000 * 0.15$/kwh ~ 0.33$/mo), it's hard to be both profitable and competitive. I'd pay maybe 2 or 2.50$ / mo, but I'm probably not a good example because I like running my own RPi at home and be able to tune things. Nice project anyway, good luck for staring your service!