I made one up out of a long scaffold pole, 4 scaffold clamps (2 for each A frame end and 2 to mount the car on) and some scrap dexion racking to make the A frames. Cost me about a tenner for the clamps, that was my total outlay.
If you have a jig on castors it might cost more as you will need to link the front and rear A frames I think? - Mine was just sat on the floor.
I mounted it to the front bulkhead, it ran through the speedo hole, then had to cut a hole in the rear bulkhead and mounted it to the top of the shock mounts.
Welded an old knackered 1/2" socket to the end of the scaffold pole, then used a wrench and a 4 foot pole to rotate the car, balance was not perfect, but as you had resistance in the scaffold clamps it only swung madly about once or twice as I was trying to rotate it.
Hope that helps a bit.