In an effort to save time and money for my 4yr. olds princess party I began at the $1 store and got each princess a Tiara and each prince a Sword .I know, I discussed this with each of the boy's parents ahead of time!!! I also managed to get all the  candy and "treasures" needed for the gift bags. It added up fast but still only came to around $25.00 I had my daughter go with me to the discount isle of the party supply store to pick out the paper supplies. Thank goodness four year olds are not picky! Nothing matched but she was absolutely thrilled with the results! Barbie hats, Disney invites, and table cloths, tea party plates and fairy napkins and streamers. For less than $10.00 I had enough for all 30 guests. Don't worry that includes adults. There were nine kids total. I'm not crazy! The fun stuff began when my husband cut up a mattress box (found at any moving company,usu. free) into the shape of a castle. VERY EASY. Just cut square shapes out of top of box. Make one bigger than others with a triangle top for the tower.  Cut a window in the tower. It makes for a great picture! We then wrapped the box around our kids slide/jungle gym (ya know, one of those colorful plastic things for the yard)and duct taped it together. We cut holes out for the slide, door and windows. This actually only took about 20 min. We spray painted it gray. And using what I had available we drew stone blocks with black magic marker, and decorated with 3D glue. We even made the door a draw sting door having it fall forward to open (don't paint door Grey, leave it brown and draw lines for a wood look). We basically trimmed the entire project with colorful 3D glue and wrote "Princess Castle" on one side. We added a flag made out of scrap fabric and a child's broom! Then topped it all off with a spray glitter. This took us about an hour. For the game we had a treasure hunt. I used a laundry detergent box and covered with contraction paper to look like a treasure chest. I made a false bottom by shoving a shoe box lid in it. I placed the gift bags under the false bottom and covered the lid with chocolate gold coins and some rings. The coins were the most expensive thing I got! My advice would be to use gold foil and wrap candy! I made up scrolls to direct kids around the yard to the next place to find a clue, eventually leading to treasure. The boys carried their swords to fight off the dragons along the way! I actually borrowed a cake pan in the shape of a castle. My daughter and I decorated it with candy hearts and flowers. IM sure you could find one somewhere for less than $10.00. It was definitely easier than having to cut and piece together cake into a castle! Finally to top everything off, my mother surprised all of us with a handmade princess gown for my daughter. I had planned on putting her Easter dress on her and letting her ruin it! She was definitely the belle of the ball!