Batch change the price on 400 files...

Hi, I recently uploaded and set all the metadata on my files (vocal work) and now want to change the price on all 400 of them. How can I do this in batch as I can't bring myself to editing each one..!
Thanks

go to uploads, on top select view 200 per page, on the right click "viewing 200" box, that will mark all 200. Now scroll to the bottom, you will see a drop down menu actions, there is a set price option, after you're done click execute.