Hi - I know its a couple of weeks since the OP but I just wanted to add to this to say I've been following slimming world since last November and have lost a stone. I do the extra easy plan and find this fits in perfectly with food my family will eat and it can be as frugal as you like. Its all about cooking food from scratch, no added fat and cutting fat off your meat ( if you use).
So, if you have basic store cupboard of stock cubes, tinned tomatoes, passata, tomato puree, herbs, spices (e.g. curry powder, chilli powder, garlic), soy sauce, worcester sauce, and make gravy from granules. Also fat free salad dressing & oil spray rather than oil.
We eat: roast chicken (left overs go to a curry or stirfry), use extra-lean mince for home made chilli, cottage pie, spag bol, casseroles from stewing beef or skinless chicken thighs. You can add as much vegetables, lentils, beans etc to bulk that out as you want, and you can eat as much of it as you need.
Lunches I have omelette, baked potato or home made soup (use any veg going past their best) or if I'm going to work I make a salad from pasta, rice, cous cous, tinned beans, tuna etc. DS & DH normally take sandwiches.
Breakfast is Aldi's weetabix or porridge with fat free yogurt and chopped fruit.
I still buy biscuits, crumpet, scones for DS snack but I just don't eat them myself, I have fruit, soup or leftovers from the meals.
If you're a SW member there are lots of tips on the website about how you can eat on a budget and recipes.
Hope that's helpful.