Many used testers are available on eBay.
http://tinyurl.com/mp9j27
For that small number of tubes, I wouldn't spend a fortune on a tester. Note that many old testers will require routine maintenance, like any other vintage electronic device. New testers might not cover very old tubes. Find out whether a given tester can handle the types that you have.
If you simply want to check for duds, you can use an ohmmeter to test for continuity between the two filament pins of each tube. You can look up tube diagrams on this website and others.
http://www.nostalgiaair.org/Tubes/
You might want to check for duds before investing in a tester. For all you know, that's a box full of dead tubes that somebody kept around for some reason.
Phil