mint green colored items to wear for formal occasion usage

Does anyone have a plus size formal maybe a 26 for free? My daughter is going to the special needs prom, night to shine in February 9, and all the dresses available to the kids free or cheap have been way too small for her. She is very top heavy and the zippers will not shut. Normally she wears an 18/20 but the dresses even the 22/24 have not fit her! She is too top heavy to wear her dress from last year. Thanks in advance mint green colored items to wear for formal occasion usage