Yup. That's what I meant. As I see it, if the primary objective is to learn more about PCB layout, I'd cancel the thru-hole board order and focus on the SMD version...which, if I understand GRJ's example, gets it down to less than $1 for 3-boards shipped? Wow. 
All I hear are crickets chirping in regards to anyone interested in buying this "tool"! The design is simple enough that it's easier to solder it together with whatever components, connectors, whatever a DIY'er has lying around and off you go. As to assembling/selling this, I think the OGR crowd is better served with more complex designs In other words, something like the DCS port tester which is a unique circuit and tedious and impractical to assemble without a PCB.
It is curious that this TVS "tester" and the DCS port tester are cousins in that they relate to the voltage spikes. This reminds of yet another widget I hand-built also simple enough as to not require a PCB. There have been several threads about it but the video is the most fun.
Again, component cost is 25 cents or so. One red LED flashes when a positive voltage spike is detected on the track, the other red LED flashes when a negative voltage spike is detected. Green LED shows power on the track. On my to do list has been to integrate this function with a 75 cent electronic "tally counter". This would count the number of spikes. The missing link is to economically simulate a button press on the tally counter whenever the voltage spike detector is triggered.
So here's a case where a PCB would be useful not so much because the circuit is complex but because you'd probably want a handful of these scattered around the layout rather than a one-off tool. Then, after an operating session it sure would be interesting to see if the voltage spikes on the layout are more frequent in certain locations, or near/follow the engine if dragged around on a powered truck as shown.
