For my 7th birthday party I had a Chinese auction. MY mother and I went out to the dollar store and a few other places and bought a variety of prizes.  We also bought tickets. Next to the prize that you wanted we put a bag. You were given about 30 tickets. You could put them in any bag you wanted.  Then at the end we picked one ticket out of each bag then that number was read aloud.  The child that had that number would go to the prize table and collect the prize that they had won. Make sure that everyone gets at the least two prizes. The toys that they had won would also be the goody bag. At the end of the auction the children could trade if they would like while having cake and other treats.