To give you some idea:
1. I've purchased a new Bushnell Trophy 2-6X handgun scope before for $100.
2. You can get a lightly used Encore stainless steel frame for in the range of $275 to $325. If it has been camopainted and not professionally done, I would deduct at least $100.
3. I would personally not pay more than $155 to $175 for a lightly used Encore or Contender barrel and generally would hold out for stainless steel. I've gotten new or minimally used barrels for significantly less than that.