Will the new ios 8 update coming will my iphone 4 no longer work at all?

Obviously current apps like Facebook an Instagram will not work but will I be able to still take pictures, use the internet text etc? Use my apps for ios 7 and lower? I heard of people using iphone 3 s still! I just need it to last another year before university before I upgrade because obviously I'm saving

You'll be fine as long as you register your device's UDID with a developer account through a site like http://www.udid.me/. It's $5, and then you can run any version of iOS.