bonstermonster20
Try Walmart or check out www.allposters.com they have a lot of different posters to choose from.

john c
If it's in your budget, "search" on Norman Rockwell. His Saturday Evening Post covers are nothing short of remarkable (especially his self portrait) and would be the perfect theme for your entire facility. Good Luck.

PiggiePants
Dollar stores sell frames for a dollar! You can easily find "art-worthy" materials to frame in old magazines, calendars, art books, fabrics, etc., that you can get at used book stores. Your organization serves children and seniors - they love to create, and love to see their work appreciated, so maybe you could buy or have donated basic supplies and have them create some wonderful, and meaningful, pictures to frame?