I saw two tube testers at the antique mall one day...

[Olorin67]

Try to get the model number on the Heathkit, some Heathkits were basic emissions testers (but still recommended if you cant afford a Hickok, easy to restore) and some were true Mutual Conductance testers similar to Hickok.
I found my Hickok in an antique store cheap, it was a bit beat up looking. They had a nice looking but basic emission tester next to it for 3 times the price...