Some good ideas already :)
You could use rice pasta and make some sort of tomato sauce, alfredo, or homemade mac n' cheese. I would add veggies and vegetarian chicken breast too! (not sure if faux meats would be gluten-free)
Homemade veggie burgers with beans/lentils/grains/veggies. Lots of yummy recipes online and you could eat yours with a gluten-free bun or in a lettuce wrap.
Caesar salad with homemade dressing, chickpeas, and coconut "bacon".
Homemade pizzas - you could use premade crusts (the gluten free ones might be a bit more pricey) and a variety of toppings.
Soups! Lots of affordable and gluten free bases (potatoes, beans, grains, veggies). You could use veggie broth for the base.
Good luck, sound like a great thing you're doing :)