I am pulling data from an API and then building out my data objects with it. I want to cache this data for the future. I have been storing the string from the api in NSUserDef
Personally I'm quite fond of the EGOCache classes, I use them quite a lot in my projects:
https://github.com/enormego/EGOCache
The classes are easy to use, I used to have my own classes with a similar design, but these are just more well-rounded, so I decided to stick with them (don't wanna reinvent the wheel).