There are tons of hotels in Honolulu, and you probably want to be near or on Waikiki beach. The harbor (Pearl Harbor) is not near the beach, but it is a short drive from the hotels (or maybe a cab). If you look on expedia you can get a good idea of cost then pick where & how much.
You should try to get a general idea of where things are in Honolulu. Look it up on line or buy a guide. You can walk to the zoo and the beach and the hula show, as well as dinner out at restaurants and other hotels on the beach. Don't skip the Royal Hawaiian, just to see a glimpse of old Hawaii.