I just give my puppies a tiny cookie and LOTS of "good potty!!" praise for going in the right place.
A quick, "NO", and move them to the right spot if I catch 'em going elsewhere.
A quick and quiet clean-up if I find it after the fact.
No gimmicks, no props, no money spent.
Hmmm, a lot like potty training my kids. . . except they didn't get a cookie, LOL.
We are training our new puppy and it reminded me of somehting I did somewhat by accident with our other 2 dogs. When we wer etrying to get them to go, we always give them a treat. At some point of frustration, I tried to get their attention and let them know we had a treat by shaking th etreat jar. Eventually, they associated the shaking sound with going potty, so with the new puppy, I started shaking the jar every time she was actually going. After just 10 days, I can shake the jar and it gets her attention and makes her pee usually, even when she is distracted and walking all around.