Seems like a can't-lose offer, doesn't it? Free developer licenses of WPF controls (Calendar, Carousel, Chart, ColorPicker, DatePicker, Expander, Gauge, GridView, MaskedTextBox, NumericUpDown, PanelBar, ProgressBar, Scheduler, Slider, TabControl, TimePicker, TreeView) from Telerik. And don't be scared off by "developer license": they say "The Developer License is perpetual and has no deployment limitations – it allows the use of the controls for an unlimited number of applications spanning various servers and domains. The applications you develop with the Telerik WPF controls can be distributed royalty free." That sounds pretty no-strings and truly free to me.
What are you waiting for? Go get your controls!