40$ for something that should be included? Are you kidding me?
You can use this script, and save it as an Acrobat Action if you need to reuse it:
The needed tools are within Acrobat, you just need to learn how to use them.
With Professional it is fairly easy to create an Action to apply to a PDF file.
You may also need additional tools to reorder the odd and even pages into the same order so you can then merge the odd and even page files.