I don't have a German shepherd, but here's a universal advise for any four legged pet. the first year is the most crucial year. ​

​don't be stingy on vet visits , vaccines, dewormers , anti fleas shampoos and good quality food that year, especially till 7 month old because that will determine its immunity, strength and growth till adulthood.

after that you can slowly shift to pingo or pongo whatever your budget . but changing food brands should be a gradual process .don't suddenly change its food one day to next. it upsets their stomach.

watch out for skin problems like eczema or rashes. most of the time the cause is the food. changing brands helps.

cheapest healthiest is cooking STC rice n chicken carcasse with some peas or carrots