Depending on the tpe of dog, depends on they type of food.

With my Vizsla I started her off on Royal Canin for the 1st year and then moved on to the Jamed Wellbeloved, however I found they this gave her a dull coat and vet excited so after speaking to the vet she recommened Nutro as this is lower in protein 19%. Ruby didnt really like this although her coat improved but the excitment didnt. So she is now on Arden Grange Light as this has low protein. She loves it and she has calmed down and looks lovely. This is also the cheapest

Royal Canin 15kg £44
Nutro 15kg £45
Arden Grange 15kg £27

These are approx prices as cant quiet remember exact.

I will say that feeding good quality food makes a lot of difference to your dogs behaviour, temp, health & the amount they go to the toilet & the amount of plaque that builds up on there teeth.

With dog food you deffinatly benifit from a good quality food.

Hope this is of some help.

Thanks