there are a couple of apps for either free food - as mentioned above or food at the end of the day at a bargain price - this might be a way of getting some sweet treats for a change
As others have said eating meals without meat is cheaper
Meal plan and cook meals for 4 people each night for 2 weeks and then having frozen the other 2 portions you can go for 2 weeks without having to either cook or purchase food for the evening meals, and not repetition for a full fortnight
chicken curry www.kitchensanctuary.com/easy-chicken-curry/
bean chilli www.bbcgoodfood.com/recipes/double-bean-roasted-pepper-chilli
coconut and lentil dahl www.slimmingworld.co.uk/recipes/carrot-and-coconut-dhal
jackfruit pulled coconut casserole yummy www.bbc.co.uk/food/recipes/pulled_jackfruit_stew_38156
chickpeas are really cheap and very healthy www.oneingredientchef.com/sweet-potato-stew/
purchased a bag of sweet potatoes so now have plenty - buy some sausages and have with mash and freeze the mash and sausages for next week.
my trick is to bulk buy jackfruit, chickpeas and lentils then I have store cupboard foods that I can easily make foods from. I like to have one weeks of he month where I don't need to go shopping and can eat from the freezer and cupboards.
a few ideas
breakfast with oats from Aldi (I like their oats the best in the green packet) tasty.co/recipe/strawberry-chocolate-overnight-oats. I use their almond milk unsweetened as its cheap as chips and lasts for weeks in the cupboard
Have a look on market place for things like a bread machine - making bread is cheaper and saves a trip to the supermarket when yo don't just buy bread. I have a milk man app so I can easily get milk delivered - it may be a few pennies more but it stops the impulse purchases