I personally love that Land o' Lakes "I can't believe it's not butter" butter spread stuff. I just like the taste of it really, and it's so easy to spread. As for milk, well there's all sorts of soy milks and stuff. I personally drink Lactaid milk. It's lactose free milk. I'm not lactose intolerant, but my mom is, and I grew up on it, and I taste a difference between it and regular milk, and I just prefer the taste. But anyways, it is still milk. I'm afraid I don't quite understand the question... You say you frequently run out of both of those, so why are you asking about substitutions? I mean it's not like you could substitute milk with cottage cheese when baking a cake. Just buy your preferred milk and butter in bulk at like Cost co.