Problem with the cheaper brands of cat food, is that there is a very high cereal content along with numerous additives which actually does make the food a little addictive to the cats eating it. (Thing kids always being fed MacDonalds and then being asked to eat a healthy meal ). Cats also get used to one brand of catfood too and will often not switch.
Try Butchers classic cat. You may well be able to get it in Tescos, it is actually at the cheaper end of the range and is very good food in that it has no added cereal, additives or Soya. The only problem is, it is very strong smelling and cats either love it or hate it.
My cat is on renal diet for kidney disease since Feb. 12 pouches cost £8.99 but slightly cheaper if bought in bulk on the internet. Biscuits £30-35 for 4-5kg bags, same applies about buying on internet. I give him a combination of both as the wet food alone will bankrupt me but he needs some moisture in his diet as he already drinks like a fish (funny expression as I don't actually think fish drink, as such, but I digress).
Cat started to get bored towards the end of the last order so I decided to try the other brand of kidney diet food. Spent £60. Cat on hunger strike because he doesn't like the new stuff. Just had to spend another £50 getting the original brand as the cat is putting on his face and won't eat. If he wasn't on the special diet I'd be inclined to sit it out and see who breaks first but if he's not eating here he would likely be eating other neighbouring cats' food and that will cause more kidney damage so I had to give in. FFS!
Before he was on this diet I was giving him Hi-Life Potty About Fish, which is about 60% real fish. Quite good I thought. No cereals or bulking agents and no mention of "animal derivatives" (WTF?). Not cheap, but certainly cheaper than what I'm giving him now. Sheba's first ingredient on the list is 4% meat and animal derivatives. Whooohooo! Lucky cat! And that's supposed to be premium brand. Shiiiiiit!