"Old" Vs. "New"
Hi Sig
What do you mean by older style? Turbomin, Sophia, JPX? These are heavy inefficient and no longer made.
Manufacturing a 12lb versus a 25 lb turbine is slightly more difficult. The main difference is the cost of the materials. Labour to machine and assemble either one is about the same.
Like Matt said, "cheap" and "turbine" don't go together. If you want a cheap turbine, expect no warranty, minimal customer service and little if any support. If your looking for a turbine in the $1000 range, that's what your going to get, IF you can find one!
Regardless of thrust or size or age, the tolerances all these engines operate at are very tight. That is the last place you want to shave cost. Unless you want to change bearings a couple of times a year.
Ed