I also noticed you said that you're a little overwhelmed on where to start. I know that feeling. I usually wander from cat food aisle to cat food aisle muttering under my breath about protein, fat content, and by products. The sales associates generally give me a wide berth lol Those three areas are a main focus btw. Read back over the list and maybe jot down a few and take those shopping with you. As far as cost, you can can catch some of those foods on sale at Petco and I found Diamond (they make Chicken Soup for the Cat Lover's Soul) at a near by Orschelin a farm supply store for a little less money.
Good luck shopping!
Good luck shopping!