Then the 'middle' priced duplex: Cryoed, Acme silver.. Several in the $50 range. And then the Oyaide and Frutech at $80 to $280.As for buying them? I would say the op would be happy with a $6 Pass & Seymour duplex.
For plugs. I used to like Wattgate. but they are just basic plugs. At $13 for the male Edison type, and $20 for the IEC. they are entry level.
IMO to actually buy the expensive separate plugs from Furutech or Oyaide, the cost plus wire in just makes no sense (from a 'bang for your buck' perspective) ... Go BUY a fully finished aftermarket power cord. Shuyata, Pangea. Some low cost entry powercord. Unless you just have to try them out..

