Your friend sounds almost as bad as DeHubby's brother's wife - I think I found eight bottles in her kitchen the last time I was over there.
Let me see - Minimum basic - salt, garlic, oregano (or Italian blend), Cinnamon, basil, bay leaf, rosemary, seasoned salt, chili powder or paprika, onion powder, Worcestershire sauce, soy sauce, and black pepper.
If there is room and they like to cook - at least one curry powder blend (Madras is hotter but sweeter than the "regular" - I buy both and mix them), nutmeg, cloves, ginger, allspice, mace, dried onion flakes (they don't go bad - like a fresh onion can), and tarragon (really good on chicken).
Although they aren't spices or herbs - baking soda and baking powder, vanilla, vinegar, and some meat tenderizer can make very useful additions to a kitchen cabinet when setting up a new house or apartment. Mint, orange, almond, butter, and banana flavorings are nice to have. Cider vinegar is tastier in salads or sweet & sour sauce (if you like Chinese). Basalmic vinegar is fabulous - but not cheap...........but in a salad dressing - a little goes a long way.
Um - at last count I had a spice rack and two Lazy Susan organizers with various spices, herbs, seasonings, and flavoring bottle on them. I used to have two spice racks - but when DeDaughter moved out just before turning twenty, I gave her the small 24 bottle rack (and filled it). It was the first spice rack that I owned and I had relabelled it with the BASIC spices (in my own opinion) that I used as a young bride...........we'd bought it for ourselves.
Have you thought about doing a search for spice racks of various sizes (6, 8, or 12 bottle racks) to check what the spice companies put on them? Or run a few of your favorite recipes through to see what seasonings are essential to MOST of them?
Salt, black pepper, garlic, baking soda, cinnamon, baking powder, brown sugar (or molasses), vinegar, and onion powder (or flakes) figure prominently in many of my recipes.