@ocelot60- The answer to your question depends on the amount of photos you want to store. If you only have a few, you should be fine starting with one memory card and purchasing more as you fill them.
You should also keep in mind that memory cards come in different storage sizes. For example, you should be able to find one that stores more than 4,000 photos. If you invest in one that has the capacity to store a lot of photos, one memory card should be all that you will need for a while.