After I blogged about Andy Wigley's port of the Perst database last night, I got email from the folks at McObject.com who are the developers of Perst.
Needless to say, they are all pretty pumped about the port, and have actually rolled Andy's port into their distributed codebase, so I would think Andy and APPA Mundi are also pretty pumped.
They sent me a press release that pretty much matches this page on their site.
Ratting around, I found a note about writing them to ask about a commercial license and thought that was something I'd be interested in knowing about, and figured everyone reading would be interested in as well. Since they began the email conversation, I have since exchanged email with them to find out all the details.
Depending upon your situation you may want to contact them, but the general case looks like this, their email in blue:
There are two prices for commercial licenses for Perst for Silverlight. If someone is running on a server with an application for client PCs who want the out-of-browser experience Silverlight provides, then Perst can be licensed for $795 for two servers and an unlimited number of clients.
If someone is building a standalone application for WP7, then a commercial license is $500 and the cost for individual runtimes is as follows:
We have a special offer at the moment where a developer will receive 1000 runtimes includes for free when they purchase their commercial license.
After some back-and-forth to get my head around this it comes down to the honor system for how many apps you sell at the Windows MarketPlace. Since apps can't be side-loaded, there's no way to insert a unique license into every app.
But, the expectation is that for every copy of your wildly-popular WP7 app, you also have a license purchased for it.
I'll let everyone do their own math based on their expectation of sales and need of a full-up database solution.