I am going to have to disagree on the Wattgate recommendation. If you are at an absolute low budget, the Wattgate are decent for the money as long as you get the "Classic" series. DO NOT get the EVO series because they use hex-head screws for the wire clamping and you WILL strip the hex insert the first time you try to tighten it down. The Wattgate use brass conductors and can come across a bit harsh. If you have to spend under $20 a plug, these are probably the only option.
I would recommend the Furutech FI-15(R) Plus connectors. They are absolutely excellent and have the same exact rhodium plated conductor/clamp assemblies that are found in the more expensive plugs. They just use a flexible plastic outer shell (but you’ll notice that the shell/case screws are still connected to ground). They are only about $62 each. I use them frequently (but I also have the really expensive NCF plugs). The only downside is the FI-15 Plus won’t support some of the very thick cables (it allows up to 15mm thick cables).
