earlier today someone asked about free/cheap component libraries for winforms. I'm interested in the same thing, but for asp.net. There are some great commercial libraries like Telerik and DevExpress, but are there any great free/cheap alternatives?
I am not sure what you constitute as cheap, but the Peter Blum ASP.NET controls are a good buy.
I would suggest that you can get free components at sites like codeproject, but you are going to end up sinking a ton of time separating the wheat from the chaff and figuring out how to use them, and since they are not a unified library the APIs and integration will be a new learning curve for each different control.
So I would recommend, unless you are a hobbyist with a lot of time on your hands, it is without a doubt worth the money for your company to buy something from Peter Blum, DevExpress, Infragistics, Telerik, or one of the other vendors who will provide support and documentation.
Check out the ASP.NET Control Gallery.
"The Control Gallery is a directory of over 900 controls and components to use in your own applications. You will find everything from simple controls to full e-commerce components."
Not all of them are free but definitely worth a look.
I'm enjoying the obout.com control suite for asp.net - $200 buys you the whole suite and they seem to be actively developing it.
The Grid and Treeview are very strong in this suite, and I've been impressed with support.