power supply issues (help me!)

Which power supply do you recommend me for Arduino? I’m facing issues with the chinese 5v and 9v power supplies. They cause the Arduino reads to go crazy, making it misbehave. When I run through the computer USB, it runs just fine! Which power supply for Arduino do you recommend me? Please need help!

I attached the picture of the 5V power supply I'm using.
I don't have pics of the 9V power supply , but it's very similar.