The gold standard at that price level is the Synergistic Research Master Coupler. So good they command around $300 even after having been made for like 30 years now. You might find one for $250, or more, but should be able to find one $350 or less. Worth the effort. If you're in a hurry then another safe bet is anything used from Synergistic in your price range. You might be able to get a UEF Blue around $350. If so that would be even better than a Master Coupler.
Ted was the original power cord market leader with the Master Coupler, and if you ask me Synergistic never has relinquished that lead. They are all very similar in sound- big, bold, detailed and across the board excellent, never the tone control you get with so many others. As they go up in price they get increasingly sophisticated and refined even as dynamics and resolution improves. Because of this its very hard to go wrong with any of them and you can pretty much buy whatever you can afford and wind up always getting your money's worth.
Ted was the original power cord market leader with the Master Coupler, and if you ask me Synergistic never has relinquished that lead. They are all very similar in sound- big, bold, detailed and across the board excellent, never the tone control you get with so many others. As they go up in price they get increasingly sophisticated and refined even as dynamics and resolution improves. Because of this its very hard to go wrong with any of them and you can pretty much buy whatever you can afford and wind up always getting your money's worth.