Hi,
There is always Ebay, you can do better on price most of the time by doing a web search for tubes, or tube testers. Many times you will find that someone selling tubes will also have some testers for sale.
Also check OLRT.com
: I would like to purchase a working tube tester with all manuals, capable of testing 7C6,7B7,41,XXL,etc. Can anyone tell me where I can find one.