I would call Scottrade and scream till they give you a better fill.. I use market orders quite a bit because I have a day job, and typically my positions are small so slippage isnt a big concern.. but every so often I get nailed/ripped off with those market maker games.. Lately they are doing that alot again at the open where they wait 5 minutes to fill you at the worse possible price whether im going long or short..
Market orders you have to allow for some slippage, but when it starts becoming 1/2 points or worse- thats wrong.. I can understand if you have a phsyical stop lose on a short in and they squeeze you for .75, but thats a short squeeze.. : )