Bought a no-name toner and probe kit off an auction site last month, figured it would save me a few dollars over the name brands. Took me an hour on a customer's line before I realized it was picking up every cable in the wall but the one I needed. Anyone else had luck with budget testers or should I just eat the cost and get a quality set?
The cheap ones usually just pick up on any live cable near them, so that part is normal even for pricier kits. A real issue is the budget probe might not have the sensitivity dial to weed out the noise.
My $18 no-name detector from a hardware store has a sensitivity dial and it still chirps at everything including my phone charger from 6 feet away. I borrowed a buddy's $140 Fluke once and it did the exact same dance near a buried line in his yard. The real difference is the cheap one tells you something's live, and the expensive one tells you something's live with a fancier beep. If you're just figuring out if a wire's hot before you touch it, the budget tool does that job. Noise is noise no matter what you pay, and half the time the expensive dial just makes you feel better while you're still guessing.