Except the entry level reg (with octo) is now at least $400. I'm looking at scuba.com and the cheapest options with octo are $400 for a Cressi or Seac set with unbalanced piston first stages. The cheapest I'd actually recommend is the Mares 15x with Prestige second stages for $424. If you are in the US and don't mind mail in service, the DGX D6 package is $450 and includes an SPG so is a slightly better deal.Better to spend that $300 on an entry-level reg with a warranty etc. that will last 20+ years with minimal care.
When that's what a new reg costs, $200 (plus hoses) for a set of serviced stages looks pretty attractive.
Used Gear - Used First Stages - Northeast Scuba Supply Store
northeastscubasupply.com
Used Gear - Used Second Stages and Octos - Northeast Scuba Supply Store
northeastscubasupply.com