For my son's 3rd birthday we had a Buzz Lightyear party. I turned our play room into mission control. I covered every wall with black plastic. I then cut stars out of cardboard and covered them with aluminum foil and hung them from the ceiling at different lengths.  I went to a store near my house that had a buzz Lightyear display. I asked them if I could have it when they were finished. They gave it to me and also gave me Buzz goodie bags that they had left over from a back to school promotion. They were filled with Buzz erasers, bookmarks, and pencils. For the other decorations I covered the tables with neon green an purple tablecloths. For centerpieces I put neon space swords that I got from the dollar store in silver coffee cans.  They were very high tech looking. For a craft I got paper grocery bags and before the party cut them up the middle and cut holes in the sides for arms (I have seen this done to make Indian costumes at Thanksgiving). We then covered the front and back with aluminum foil. I let the children write their names with glitter pens, and stick on star stickers.  These were their space suits. This was an awesome party and since most of the suff was donated it was very cheap. Since that party I've saved a lot of money asking stores for their extra displays and promotional items.