Here you go Andrew,
Here's how to build a cheap pyramid (cousin to a saucer) easily. I built mine in a couple hours, not including glue curing.
Get a 1 inch x 2 ft x 8 ft sheet of extruded polystyrene also known as "blue [also comes in pink] board" or "Dow [also made by Owens Corning] board" at your local lumber yard/Home Depot/Lowe's. That should not set you back more than $20. Cut three 2x2 foot right triangles with a 45 degree bevel on the sides. (A table saw would be best, but a skill saw would work. You'll want adult supervision of course and a dust mask would be a good idea. Do they still have shop class in middle/high school?) You'll have plenty left over to build another later.
Glue these together with polyurethane glue like "Gorilla glue". Be sure to tape the pieces together well as the glue expands. It will look like the corner of a box if you sit it on one of the sides.
You'll need an equilateral triangle of foam and a plywood centering ring for a thrust plate.
. A 3.9" to 2.14 (54mm) will be $8.91 from LOC Precision. (Alternatively, you could make one in shop for next to nothing.)
I used a 7 inch length of 38mm motor mount tube I had lying around. However, it would certainly take a 54mm motor mount? I have flown mine a couple times with a CTI J381 Skidmark. On the other hand, it also flies well on as little as a single grain 38mm Tiger Tale EX motor. 10" of 54mm motor mount goes for $2.89 from LOC Precision.
Finally, you'll need a launch lug to fit your needs and rod availability at your club. I used a 1/4 inch lug. Six go for $3.03.
It looked good originally painted black. Then I used spray adhesive to wrap it with a space blanket to give it the "futuristic space" look. I haven't decided if I like it or not. It might have been better to use three separate pieces instead of one wrinkly wrap around the three sides.
I hope this helps,
Matt
Thanks to Howie Druckerman for showing me this idea.