I use Ultimate CSV Importer for my sites, so the free version of that should be just dandy.
Edit: as another suggestion, allow us to upload media files independently. I'm sure there are reasons why you want to avoid this, but currently, all images are appended to a post if you bulk import them. Also, giving us the option to remove the /2013-10-10/ before an image would be cool. This is a function you can do in wordpress quite easily, so I hope it translates without issue.