my imac is switching off my USB stick

I am new to using the iMac and still need to use a usb stick to transfer data from my computer to other devices. I initially put an old usb stick that I had been using with the pc into one of the ports at the back of my mac and I got an error message that it was drawing too much power and has been disabled. A friend told me that this could be due to them being old and to get myself some new ones.

I purchased two Verbatum store n go drives one I put staight into the iMac which did not work and one into the pc where it was recognised but then into the imac where it was not seen even in finder. I put this usb back into the pc where it no longer worked. I then purchased a lexar jump drive and this is not seen in the iMac.

I am able to use a small printer on USB and we have a external hard drive for time machine. My husbands stick which he has had for a couple of years also works. Any one have an idea what is going on and how to resolve this, I need to be able to use a stick to transfer files.