Ral Partha miniatures made for Dark Sun pop up on ebay and other used dealer from time to time and are becoming fairly expensive. Furthermore, their "true" 25mm scale doesn't match up well with the 28mm heroic style of modern miniatures. Luckily, it is not to hard to adapt current minis into the Dark Sun world. Athas is hot, arid and metal is very rare. So lightly dressed character in leather or fabric, and weapons should appear to be bone or stone. High ranking character would have metal weapons, but they are rarer than a +2 sword in a typical campaign world.
This figure instantly screamed Dark Sun to me. Athasian elves were speedy runners and the none too smooth finish on the weapons could pass for bone. As part of the Reaper Bones line, I found some of the facial detail a little less distinct than on the original metal figure. However, the weapons were well molded and straight, and did not require the boiling water dip to reset them.
Reaper Bones Iconic Elf Merisiel
Also worth getting from a few years ago is the IDW graphic novel Ianto's Tomb. It's less epic than the five book series but the artist does a great job in capturing the look of Athas as many imagined it.