For the love of all that is holy please do not feed them Bakers or Pedigree Chum. Both have very little protein content (which is essential for a growing pup), and are very high in fat and sugar which will make your dogs hyperactive and give them runny poos.
Good quality food does not have to cost you much. My GSD lives on a diet mostly of dry food, some wet mixed in and every now then she has some raw. Right now she is eating Country Choice Chicken and Rice which has 65% chicken and rice. The higher the percentage the better. A 15kg sack costs me only £18 from my local petshop.
If you're thinking of using the Pets at Home own brand dry food then don't. A 12kg sack will cost you £28!!!!! and it is less nutritious than Country Choice.
Other good quality food includes James Well Beloved and Arden Grange.
If you wish to feed wet food the best (if a little expensive) to get is Nature Diet. It's all natural, nothing artificial. Nature Diet is a bit expensive for me, but my GSD does well on Morrisons own brand tins! (We often substitute with Country Choice tins)