You'd probably have to share some expectations of what you need done, beyond just pixel art. Including the style of the art as well, some pixel art is a lot easier to draw than others. There's also huge difference between slapping together some graphics for Flappy Birds compared to say, an RPG with a bazillion items, character animations, various monsters, world map art, etc. I could do all of Flappy Bird's graphics, including the GUI/Interface in a day, and it would even look better! But, to do a full scope small RPG you're talking 6+ solid months (and that's a conservative estimate)
Having said that, depending on what you need done, $2000 may not be enough to hire a really skilled pixel artist, or it may be excessively overkill.