Well, first off, you get what you pay for...I'd not use those inexpensive outlets. But, you need to separate the hot inputs to the outlet. There's a little tab you can ben back and forth until it breaks. That will make each outlet separate, and your switch will be able to control one. Right now, regardless of where the switch is, because that tab is there, hot is connected to both outlets. If you have the old one, you should be able to see that tab was removed. Depending on how it was wired, you may or may not have to remove the neutral side's tab.