I don't eat much meat and I cook from scratch so I can keep it below 30 easily. Eating out socially a couple of times a month tends to cost more than the grocery bill for that week. And I don't drink at home.
I find living alone helps with eating cheaply because I only need to have food I really like. So think about what good value foods you really like. I like root veg, kale, cauliflower, mushrooms, beans of any sort, wholemeal pasta, seeded bread, cheese, butter, peanut butter, tuna, mackerel, couscous, oatmeal, barley, eggs. I try not to have too much sugar in the house because I would eat it up fast, but I have jam or honey which means when I have something sweet, it's filling. I love my food, but it's my food, my favourite things (apart from chocolate and cake).
I shop mostly at Lidl and Iceland but I go elsewhere if I want anything they're got. I do vague meal planning around two main carbohydrates of the week (baked potatoes and pasta this week), with lots whatever veg I fancy and lots of wholemeal bread and oatmeal. I track my nutrients vaguely and take a multivitamin with iron (included in my food price). I find that if you're having lots of whole foods, your appetite feels well under control. I am probably a bit more of a repetitive eater than lots of people but I really do eat what I want. So try to find cheap combinations you love and build them up into something even more filling and nutritious.
I have spent £57 at Lidl this month, according to my app, definitely not more than 5 elsewhere, 80 eating out but these were five separate social events, not needed for food.
I find not having too much of anything - so you get sick of it or it goes off - or too little - so you "panic buy" or have cravings is the challenge, living alone, so I avoid big shops. I find 2 or 3 trips to Lidl a week works for me, and helps me to see how much bread / milk I need for a day / week, and gets me in a rhythm of planning and small-scale bulk cooking.
That works for me but something completely different might work for you. Start by deciding what you will enjoy.