I have no idea what kind of shoes you like, but you could try some of these
http://www.asos.com/Mary-Kate-Olsen/Asos/A...=-1&clr=Tan^^ this pair, is on sale. I love this site and recommend it. I would definitely stick with a light, nude colour with this dress. As for why they show the model wearing that colour, is probably because it matches the belt. Since the belt is not with it, you're pretty free to pick any colour shoe. But like i said, i would stick with a light or nude colour.
http://15dollarstore.com/p/miss-me-cut-out...umps/1623985937^^ this pair is cute *.* i think it adds "texture" and will pull out the "soft" girly-ness of the dress. The lavender dress and the white shoe would make it a sort of "lullaby" theme, and will draw attention to you shoe.
http://www.aldoshoes.com/us/sale/women/san...95107-sibrel/28^^ this shoe is a bit more than you said you'd like to spend. But its a bit different style than the others, and may be well worth your money. Again, its a nude-ish colour, it has thicker straps and would provide more dimension to your outfit because the "line" of your dress is thin.
I hope i was of some help >.<'
happy shopping (of course) ^.~`
xx
EDIT:!!
If you click the third link, make sure you click the "BONE" colour option!!!
and the first link!!! SECOND COLOUR OPTION, not the black ones!!