When you look at your earnings (@
http://www.dreamstime.com/earnings), what does it say under the Price column?
Most of mine say "xx credits (2008)", where xx is some numeric amount.
I'm wondering if yours says something different.
What does it say under the Resolution column and the License column?
Under the DT image pricing site (@
http://www.dreamstime.com/level.php?lvlimag=2#2), it states that a 12 credit image should be priced no lower than $9.24 (for a Level 4 or Level 5 image).
The only thing I can think is that this sale might have come from an "affiliate" site.