On the main bootcamp thread there are links to the carb content of all veg. I generally stick to salads, green veg , aubergines, courgettes and mushrooms. I also shop in Aldi or Lidl, Aldi usually have 6 fruit and veg for 69p.
Frozen chicken thighs for example are cheaper than fresh or ready cooked, you just have to be more organised and remember to defrost. Farmfoods also does chicken/pork/ salmon quite cheap. Or most of the big supermarket have a short dated whoopssection where you can pick up real bargains. Or frozen liver is really cheap.
Milk I dont know, I just buy double cream and use sparingly. Hth