Hi Ed- Putting together a kit/supplies on a budget is tricky enough, add in disabilities and allergies and it makes it both much trickier and much simpler.

The folks here are terrific sources of info and I've learned a lot lurking here.

For the tight budget part, there are some common strategies such as smart use of your Dollar Store or equivalent. Lots of folks report finding good equipment at estate sales and thrift stores like Salvation Army or GoodWill which both have online stores. Watching for sales at the bargain stores ( here those might be Smart'n'Final or WinCo, not sure about your area.)

Allergies, depending upon the specifics and severity can be very significant challenges. At minimum, CAREFUL reading of labels is most important. If the allergies are the biggies that are increasingly being diagnosed such as, gluten, casein, nuts, chicken eggs, corn, you have lots of company these days. There are good online groups - often of knowledgeable parents who have truly pioneered the searches for safe foods.

Then there are the issues, after deciding on which foods are safe and can store well, of exactly HOW to store or in what form to buy in order to store well. If you don't have a countertop vacuum food saver, you might contact you neighbors or a local LDS to see if they can help or can advise you. Again, on the food saver, that can sometimes be found at the thrifty suggestions, above, or the LDS cannery may help you out...

Without knowing your specific allergens, Amy's Lentil Soup and Lentil Vegetable soups are relatively allergen free. Our COSTCO sells six or eight cans in a small case. If nuts aren't a problem, a glass jar of nut butter can be a good ready to eat food that needs no cooking... Plain canned beans (saves on water and fuel) and instant rice are great staples that can be dressed up with herbs/spices to offer nutrition and variety.

Steer clear of foods that go rancid quickly such as brown rice and foods not packaged in glass...

Without a better idea of some details, those are some suggestions just off the top.

Honestly, YouTube is one of my favorite resources for seeing how others prepare on the cheap or on a budget. Definitely do-able! Let us know about your progress!