From the size of the picture it is hard to tell, but it looks like a Yellow Labrador.

(Granted this picture is of a Black Lab, but the head shape is still the same. lol)
Some other breeds that it might be, these came to me afterwards, are:
A Rhodesian Ridgeback
Or a Chesapeke Bay Retriever
Just remember to buy a dog not based on looks, but based on the breeds temperament and other qualitities like activity level, shedding level, and gromming required!
