1) $20-40/yr for a web service. Most of the world is Windows, so if I'm on the go without my OS X laptop, my phone has died, and I want to check my email I'd have to remember my other email passwords to login to their own services after I got in the habit of using Inky... that wouldn't be good. I'd still want data security, so I'd expect any data that hits your servers to be strongly encrypted in a manner similar to SpiderOak's approach (though I'd prefer Scrypt over PBKDF2). If you open-sourced your client and just sold the service I'd pay more. 2) $50 for the app itself. Less if you want me to pay every year for upgrades.