You might look at the Peter Alway kits sold at Balsa Machining Services. The Arcas is a BT-50, IIRC, and is $13. There is also the Astrobee 1500 which is more complex, but is a really nice piece of engineering with laser cut parts. Heck, order both and learn with the Arcas and then progress to the more difficult Astrobee.
I was the first NARTREK chairman back in the late '70s.
Chas