HO Scale
A guy has a limited budget, but could still get some descent models:
An Athearn Genesis 2-8-2 in the box for $30
A Rivarossi 4-6-2 for up to $35
Rivarossi Y6b for $35
Rivarossi Hudson for $30
An Old Champ 2-6-2 in the box for $20
A GHC 4-4-2 for $30, in the box, and a USMC Toys for Tots...