McDonald's has Big Macs, Filet-o-Fish, 10 pc McNuggets, and Classic Chicken Sandwiches (mix+match) 2 for $5 (thanks thecompdude). You can stack that with the $3 off $10 (mobile order) promotion. Apparently the mobile order promo is looking at original full price of the items. Total comes to $2!
If you're lucky enough to be in an area where these items are <$5 full price, you may be able to customize them to make them over $5 each, or add additional items (thanks tuanp).
YMMV and Good luck!