Apple ID and Primary Email Address - providing that I change my primary email, will my purchases be kept? as from the title, providing that I change my primary email, will my purchases be kept? I'm stuck at https://appleid.apple.com and trying to figure it out.

Thanks
If you change your primary email, the purchases should be the same.  As long as you hit "edit" next to the primary email address field of your AppleID on appleid.apple.com, you should be fine.  Call AppleCare if you have any questions, they should be able to answer your AppleID questions.