Check out Seattle Thrift stores for ideas for your twins. We recycled old red sleepers, blue ski hats, and used some recycled office supplies to make costumes for our twins.
Our son, however, did get a new Cat-in-the-Hat costume.
Our rule is, do what you can, when you can. If recycling and reusing are not convenient at the moment, just make a promise to yourself, your kids and your family to try again, while staying sane and enjoying the time you have! Happy Halloween.