and looking at costs it seems to be pretty expensive- or am i wrong
You should be fine taking fish oil pills. Go to walmart and buy a bunch. But you do need cod liver oil in liquid. If you can't find any take a vitamin A supplement a day and raise the fish oil amount as well as taking one extra calcium + D supplement to get all of the vitamin D your body needs daily in case you don't go out much.
Whatever you decide to do let me know and I can advice you to take exactly how much