If you want to test a valve the tester is hard to find at any price.
Valve testers weren't ever of much use anyway, we had one in the workshop (which got destroyed in a fire), but it wasn't something we ever used - apart from the occasional testing of valves that customers brought in. They only provide a very limited testing capability, and normal fault finding is far superior and faster.
We did have people sometimes bring ALL the valves out of their TV for testing, and then couldn't put them back in the right places afterwards
Another meddling customer brought his B&W valve set in, and said "I've tightened all those loose screws inside, and it doesn't work now" - he'd screwed all the IF cores down to the bottom!
Most bizarre repair(s) I ever did was to a GEC B&W valve set, it came in as faulty, and a number of wires had been cut inside it. I repaired the wires, the set worked fine, explained that it had cut wires inside, charged the customer and gave it him back. The customer was actually a local veterinary surgeon, and lived about 1/4 mile away.
Next day he brought it back, complaining that we hadn't repaired it properly, as it still wouldn't work. So I took him upstairs, removed the back in front of him, and showed him yet more cut wires. I showed it him working, refitted the back, and applied paint to the back screws, so it would be obvious if they were removed - we charged him again, as it was no fault of ours. He also denied all knowledge of what might be happening to it.
Next day he brought it back
AGAIN, and pointed out that the paint hadn't been disturbed, but careful examination of the back showed where something long and thin (such as surgical scissors) had been squeezed through the slots in the back. Needless to say, the only fault was cut wires - so we charged him again
We pointed out, again, that someone was deliberately sabotaging his TV, and that perhaps he ought to find out who and why, rather than paying us for simple repairs every day.
After that we never saw him or his TV again, so I've no idea what it was all about.