I made my own back in the 80's. I started out by selecting some suitable materials and wouldn't you know it a broom handle was just perfect. It only took a couple of weeks for my wife to complain that broom handles were too short .... Anyway, they worked ok at the time. The ones I made were blue and white and pretty basic but way back then fish weren't as smart as they are today and they did catch fish. I caught a load of kahawai on them, which is not really a target species for topwater fishers but I did get the odd rat. I'm sure if you used a 32mm dowel and a little artistry then kings would climb all over them.

May not be a huge cost saving, but the satisfaction of catching a fish on a popper you made is priceless.