dotnet widgets is free , divil is a top programmer ( if you visit http://www.dotnetforums.net you will see him there ) i would recommend using it if you dont want to build something yourself.
the only time you would be charged for it from my understanding is if you dont wish to include divil's name in the credits for the dotnetwidgets ( ie: try to make it look like your work )
this is direct from the Licensing FAQ section:
I get asked lots of questions on the licensing of my controls so I've prepared this page to hopefully clear things up a bit.

Can I use your controls in my commercial application?

Yes, you can use my controls free of charge without royalties as long as my name appears in the about box (or similar position) in the application.

Can I obtain source to your controls?

No. With the exception of the OurlookBar control, all my controls are closed source. If you find a bug and report it to me, I will fix it. Should I ever stop supporting any of my controls I will make the source available for them. I don't offer the source for sale.

What if I don't want to include your name in my application?

Contact me and we can discuss pricing.