If it's the Antec True Power Gold TP-650G model made by Delta Electronics then it should be a good unit. $50 would be a great deal for this one.
If it's the discontinued True Power New TP-650 model made by Seasonic then that one should be good too.
If it's the discontinued True Power Trio TP3-650 model made by Seasonic then stay far away from it. JonnyGURU blew up two of them during their review because this unit couldn't handle a heavy +12V cross load in a hot box.