Buy in bulk when possible. Depending on what you like cooking, though, only some things are worth buying in bulk. I personally like to cook pasta so I always have pasta. Stock up on things, and don't always buy things when you need it (save for special occasions and what not).There are some substitutes for ingredients if you don't have a particular one. I find that the internet is best helpful for recipes; you don't have to follow them exactly, I like to tweak them all the time. Doesn't mean it'll turn out worse.