I like the dragon, and the elf-thing, too. They're OMGKAWAII.
Mm, if you colored them in, like, photoshop or something, you might be able to get around 10k for that first one (the one that isn't a link). Then you just add 5k for waist up, and another 5k for fullbody? I dunno. I've seen some crazy expensive artshops, and also some cheap ones. I guess it just depends on how much people are willing to spend on your art, first. Perhaps start with bribe only slots, to get an idea of what people are willing to pay.