2003 Neon SE fuel gauge issue

I have an 03 Neon SE, that only shows a little more than 3/4 full after getting a full tank of gas. After that, the gauge seems to trickle down normally, but is still about a 1/4 tank off. Is it likely the sending unit, or the gauge itself? Anyone have an idea as to how much it would cost to repair?

Nevermind, must have just been the pump I was using.