I used Barking Heads Puppy Days for my puppy until recently and he seemed to thrive on it - but it has oats in it, so not completely free from grains. I've just moved him on to Acana, which is 40% protein (the Orijen at 80% seemed a little rich for me, somehow). The decent quality food doesn't work out much more expensive, and if you buy in bulk it works out cheaper (so once you've found one you like have a look at Amazon, or places like PetPlanet.co.uk). Highly recommend a decent quality one, though, as there is usually less poo which equals more sleep!!
Good luck with the new pup! We need details of the pup (and photos)... so we can all get nostalgic for when ours were tiny wee things!