It is tough to define relatively cheap.
You can do rubies which are basically toys for about 30 buck
Resin copies......from 70-200 bucks
metal alloy copies 250-600 bucks
Master Replicas 700-1200 bucks.
I have a set of resin cast that cost me about 75 dollars. They look decent and are good for trooping. I would consider them to be a relatively cheap avenue. As far as getting a hold of some you have to watch the cargo hold or do some real searching, they aren't really advertised.
That's my 2cents