Say you are looking for a free or inexpensive alternative to an expensive application like Photoshop. Solution: Go to alternativeto.net, search ‘Photoshop’ and feast your eyes. Then filter the search results for ‘Free and Open Source’ and feast your eyes again.
A right smart and terrifically useful web site. Applications are rated by users. Go there before you buy any software.
Example: Search results for ‘Photoshop’