nursery must haves?

i am currently expecting my first baby in just a couple short months, and my SO and i are beginning to start on the nursery. seeing as we've never done this before, we don't really know exactly what you need and what you can pass on. is a crib better than a co-sleeper? do you also need a bassinet if you have a crib? we're trying to get by as cheaply as possible because we're trying to save for a newborn, but we don't want to skimp out on the necessities. any advice?