Q: How can I store all my photos and videos from my iphone4 to the cloud? And once I have, will I be able to delete them from my phone to free up space so that I can take photos again?

IM sure you have learned how to do the transfer to a secure none syncing when you'd like to save them somewhere task in your question as I respond in late June but incase you have not I found this  https://www.quora.com/How-can-I-delete-photos-from-my-iPhone-but-keep-them-in-iC loud

You will have at best, iOS 7.12 I think.

Your photos are "safe" in the cloud, but that does not mean you can remove them from your phone after uploading.

iCloud is a syncing service, designed to maintain the same content on each of your devices. It uses the cloud as your reference point for that syncing. You can't simply "move" your photos to the cloud and carry on making more photos.

You should read up on the features of iCloud Photo Library, as that sounds like the feature you want to use.

iCloud Photo Library FAQ - Apple Support