just a few questions about what to buy...

with the tuna, does it matter what kind of tuna i get?...some cans cost double the amount of others...right now im buying the gold seal yellow tail one at costco...would the more exspensive tuna be better for me? or is all tuna in the can the same?..

oatmeal, should i just go with the rolled oats?..or is there something better out there??..im gussing the the pre-packaged ones with fruit are no good? too much sugars?