what you buy totally depends on you. are you cooking for one? don't buy 6 pounds of fresh salmon cuz you'll never get through it. do you have access to good fresh seafood? consider the source. i won't eat any farm-raised fish.
chicken is easy to batch cook for the week or use in soups and stews. you can also use small bits in stirfry. i don't find it as satisfying as red meat so don't eat it all that often.
do some web-surfing for primal recipes and see what looks good before you spend buttloads of dough on food.