Evernote is a great note taking and keeping app. You can create notes and notebooks that will sync too all your devices & computers. You can even share these with others. You will have to create a free account at their website, install the applications on all of the devices you would like to have access to your files. The service is free as are all the apps. If you find you use more space you can always buy more space via their premium upgrade. There are also many nice add-ons to use with the basic Evernote app. Some are free some not. Check it out. Once you start using it, you will wonder how you ever went without it!
Get it at the App store: https://itunes.apple.com/us/app/evernote/id281796108?mt=8
Evernote website to set up your account and view tutorials: http://evernote.com