They pop up at swap meets if you know what to look for. I now have 2 for the T. One is on loan to a friend. If you need it and can't find one I will loan one out to you. They are a bit pricey if you consider their simplicity. I really liked the one in the picture so I went all the way up to $15 to buy it. They usually sell at about $5... sometimes less if the seller doesn't know what a rare treasure he has.

The one I have on loan was machined by a friend on his lathe and is really nice, he made it to fit his Overland Touring. He sold the car and so sold the spoke jack. He even put the pressure plate on a ball and socket joint! The fellow who is using it reground the pointed end to fit a model T better. So if you get one at a swap meet you can modify it if you need to. Beware however, I found one for my Buick which has much shorter spokes... they are available in a size too short for the T! It would be a disaster to spend $3 and then have it too short to use!