Last I saw, the basic real server for up to ten simultaneous streams(speaking from memory) was free. It is also possible to stream .ra files through HTTP.
1)You need these mime types on your server:
audio/x-pn-realaudio rm ra ram
audio/x-pn-realaudio-plugin rpm
2)Create a metafile which points to the .ra file in this format:
http://hostname/path/filename
3)Save the metafile as a .ram file
4)link to the metafile from your web page.
