How do I transfer all the photos and videos within messages to my computer?

How do I transfer all the photos and videos within messages to my computer?

I want to transfer all the pictures and videos within my text messages to my computer. I am looking for the quickest, easiest and cheapest way to do this. I prefer to transfer the images to a PC but I also own a MAC. I have too many images to consider saving them one-at-a-time to my camera roll as a viable option. Third party software or apps would be acceptable if not too expensive. Under $5 would be great but I may be willing to pay more. I prefer not to jailbreak my iPhone. Thanks for your advice!