While I'm not necessarily referring to the newer iPod Nano models, the iPod Nano in general is a cheap Apple product that is overlooked most of the time.
If you've thought about getting a dedicated music player for the gym or in the kitchen, the iPod Nano is a great device for that.
The best part is that you can get older iPod Nano units for next to nothing. You'll be able to find 2nd-generation iPod Nanos on eBay selling for less than $30. That's not a lot to pay for a music player at all.
Of course, you could just use your phone, but sometimes you'd rather just have a small music player that you can take with you to the gym so that you don't risk breaking or losing your iPhone.