Buy a Sandisk Clip+ and Rockbox it. Rockbox is a free alternative firmware(operating system) which has many great features.
The Clip+ has a micro card slot. A 4GB Clip+ is $35 on Amazon. It has great sound quality. The Clip Zip is a bit better than the Clip+
when Rockbox is installed, as the Clip Zip has a larger screen. Avoid the Clip Sport though as it is very limited in functionality. The Clip Zip
without Rockbox is annoying though, as not enough song information is displayed. The Clip+ is okay without Rockbox, but much better with it.
I have the Clip+, Clip Zip, and Clip Sport. My Clip+ and Clip Zip are Rockboxed. There is no Rockbox available for the Clip Sport.
My main complaint about the Clip+ and Clip zip with Rockbox installed is that battery life is only around 15 hours. Some who need more
battery life carry two of them, or the player and a usb battery pack.
The Fiio X1 has battery life that is probably less than that of a Rockboxed Clip+ or Clip Zip. the X1 though has a much higher power output, which can power less efficient headphones. If you are using relatively efficient earphones or headphones though, the Clip+ or Clip Zip will work quite well.
The Clip+ and Clip Zip are tiny, lightweight, and have a built in clip, so you can clip the player to your shirt. The X1 is much larger and much heavier.