An inexpensive and cute centerpiece that I did for a birthday party was using the 32oz chinese take out containers! Since they are white, you can decorate it to your decor. I cut and taped clear party bags to one side and used stickers on the other side and filled it with candy (or cookies, or your idea.)
The handle is great to tie balloons on, and the guest can easily carry it out when they leave. I purchase them on E-Bay for about $10.00 for 24. You can use the leftover boxes to pack extra desserts in. I am a firm believer in giving things away to guests who took time to be there. It makes them happy and I don't have to carry it home.
YOU CAN GET THE CONTAINERS REALLY CHEAP ON PAPERMART.COM. I WAS PRICING OUT WEDDING FAVORS FOR SOMEONE AS A FAVOR AND FOUND THEM FROM 11 CENTS FOR A PINT SIZE, 9 CENTS FOR A HALF PINT AND YOU CAN GET QUART SIZE ALSO. I KNOW IT MAY BE MORE THAN YOU NEED, BUT FOR THE PRICE AND THE VARIOUS SIZES DEPENDING ON YOU NEEDS I THOUGHT IT WAS GREAT.