Well that's a well-supported combination at least. Not sure the best way to save money other than to find a compatible section of collapsible shaft at the junkyard on a GM vehicle of some sort.
Ours will run you about 225 or so (
http://www.wildhorses4x4.com/category/Bronco_Steering_Shafts), including the two halves (3/4" and 1" DD), the two yokes (u-joints) and the boot and spring. But if you can find an existing OE application using the same combination that's still in good shape, I'm sure it would be much less expensive.
Not sure what your other options are frankly. Didn't know you could even get splined shaft stock. And not sure you'd really want to. If you're going to go to the trouble of making your own from aftermarket parts, you might as well go collapsible (slipping the two sizes inside one another) for safety, and all the normal stuff is DD anyway.
And since you can't mate up just a shaft, you need a yoke at each end, or a rag-joint at the upper end at least. Which is where the money goes anyway. The shafts are cheap compared to the yokes.
Good luck though. Let us know which way you end up going.
Paul