Look around on DeviantArt if you want to work with something cheaper. Sprite animations are somewhat-maybe-almost easy to find at around $20 a frame, possible to find someone that goes down to $10 or so. Even then to get a stable running animation for a 2D platformer it's going to be around 4 frames for each direction(left/right 8 total), min 5 for jumping, Some idle's lets go with 6, damage/death for another 4. So even going cheap that's still around $500 very quickly for "simple mechanics".
There is of course another route of using art already made. A bunch is free for use for all kinds of work ranging from commercial to open source , and for other misc. work that the other didn't attach a license to they're usually willing to allow use for commercial work at a pretty nice discount. Some artists even love working for open source projects and lower their prices to around $1 a frame, and maybe around $2 an hour(these are a pain to find, and are catch-22ish since you'll need proven and quality work AND you can't ask for this pricing).
As weird as it is "simpler" art like what you posted can actually end up A LOT more expensive than a larger sprite. The spriter needs to spend a lot more time getting every pixel perfect, since each pixel changes a larger amount of the piece. The amount of experience required to make your version of simple is just higher.
Even using fewer frames is likely to push a price up instead of down.
When hiring an artist just treat is like you're hiring a programmer so many of the same type of issues can show up(I'm assuming you have programming experience).
You also need to think about this: Do you really want to hire someone that does not have other people/projects competing for their attention(forcing prices up), there's possibly a reason.
Edited by lithos, 07 April 2013 - 11:26 AM.