You really can't go wrong with rice and beans. Like others have said, buy them in bulk; just make sure you have the storage vessels/space necessary. Frozen chicken breast is also cheap, easy to find, and easy to cook. It can get boring after a while, so you should try and learn a handful of recipes using those three ingredients as a base. Budgetbytes can be helpful with that.

I've been using atob for a long time; I never really felt how steep the learning curve could be, since I've been there for the addition of a lot of features. It's worth it though, it's a really silly place to pass the time, and even have a good quality discussion every once in a while.