Pasta is FINE if you want to lose weight.
I wish people would stop perpetuating this myth that carbs are the devil's henchmen. I've lost a lot of weight and I have not reduced carbs, I've reduced calories.
100g pasta (which is a perfectly acceptable portion size) = 350 Cals.
Half a 400g can of chopped tomatoes = 45Cals
Couple of garlic cloves = 10 cals
100g onion = 40 cals
100g red pepper = 40 cals
1/2 tbsp olive oil = 60 cals
4 TSP parmesan = 50 cals
Add some herbs and spices and that's a perfectly acceptable (in my opinion) dinner for 600 calories.
You need to choose your produce wisely. I'm not in the UK and memory fails me, but potatoes, carrots, cabbage, onions, apples, oranges, bananas should all be cheap. Berries and exotic fruit are always expensive. I don't find apples particularly inspiring so if I need a not too high calorie pudding, I'll chop a couple and bake in the oven for 20 mins with 2 teaspoons of sugar and some cinnamon (less than 200cals).
If you think you don't like lentils or beans I'd recommend trying the many varieties available and experimenting with some recipes. I didn't really know much of the lentil before I started calorie counting but I wouldn't be without them now. Red or yellow lentils are great for Indian recipes, kidney and black beans great for Mexican, chickpeas for Moroccan or I make a really nice chickpea paprika dish. If you can find black lentils (beluga lentils) they are DIVINE with a poached egg or halloumi. Eggs are also great for making cheap and filling food. Today I had a 3 egg omelette with lots of Fried mushrooms and a small can of sweetcorn (506 calories including butter).
It does take some getting used to and juggling around before you figure out how best to make best use of your calories, but if you persevere then it will all fall into place.
Soups can also be super cheap - yes you can have with bread! My favourites are pumpkin, Italian bean/minestrone, cream of (frozen) sweetcorn, cream of (frozen) pea, beetroot and sweet potato...