[frizzen]

There are several really amazing Trommel builds around here, or if you can get by with lower tech you can make sets of Grizzly Bars. They don't have all the cool moving stuff, and without making a conveyer your loader is going to be busy transfering material to the next one, but it classifies materal.

Cheap and Construction don't usually go together very well, but there are a few ways around that. For small equipment it's worth checking out some Bruder rc conversions, modifying pressed steel toys. If you get in with a local group, sometimes people are upgrading to a better machine and let their old one go much cheaper than new.

If you've got interest and tooling capibility, making Cable operated machines can be cheaper than Hydraulic ones. Although there's a different learning curve to running them.

What are you wanting to start with?