Need an inexpensive electric field mill for a project

Working on a little hobby project and have decided I need an electric field mill to make some measurements. Since this is a hobby I don't want to spend a huge amount.

I looked at the Scientific American Amateur Scientist project in July 1999.

Byt with my mechanical skills, building something to spin a cake pan at 7000 rpm while tightly nested inside an office trashcan sounds like the basis for getting me onto the World's Stupidest People television show if anything would.

Some of the other descriptions on the net seem a little more plausible. Google for build electric field mill and you find examples.

But I am also rational enough, I think, to realize that many of the things I think I might get around to building never really do get done. So I'm beginning to wonder whether buy, perhaps used, might be a better option for me than to try building.

So, anyone have a mill they think they might not really use again? Or know of one somewhere that might be a plausible price?

And the next item on the list is a very stable magnetometer that can measure tiny geomagnetic changes over long periods.

Thanks for any ideas