We make regular donations of about £5 and it helps me to think in terms of meals. So I try to go for:
Carbs: tinned potatoes, noodles/pasta (flavoured and plain) crackers, instant mash, rice, and a cereal -- all supermarket basics
Protein: Chickpeas, beans, tuna (if a very good offer as is £££) these days, tinned salmon can be cheaper, canned spinach, nut butter (not all FBs allow nuts) dry soy mince, sardines, marmite.
Tinned veg (some in every donation) Tinned fruit in juice
Fat: Cooking oil, soya cream uht, uht milk, marvel, cakes, biscuits (some gf too when on offer) rice pudding, custard tins, carnation.
Store Cupboard: stock cubes, tomato puree, salt, pepper, spices and sugar, jello as in brand, not Americanism
Toiletries: Loo roll, toothpaste, soap, Sanpro, nappies if go to Aldi, deoderant, sudacream, lip balm, plasters, savlon, floss, shampoo, shave foam, razors
Household: I save samples of washing powder, as I cannot afford to donate it too regularly, jay cloths, spray bleach cleaner, loo cleaner, sponges.
Occasional donations -- sweets and toys at festival times our local paper publishes these dates for all established religious groups, follow on milk.