Small Engines (Lawn Mowers, etc.): weedeaters, ryobi gas trimmer, google

Question
where can you find a new carburetor for a ryobi gas trimmer  

Answer
Do you have the old carb?  If so, there is a manufacturer brand name, typically Walbro or Zama, and there is a model number such as WT-109 or C1A-79.

If you have the model number of the trimmer you can find the carb here:

http://www.outdoordistributors.com/ryobi/Ryobi_Search.html

The whole carb is typically $30-$90.  Once you have the part number Google it for the best price.

Let me know if this helps.
Eric