Half a pound of salmon costs around $7-8. If you wait till it's on sale, you can do a bit better. However, half a pound is still 450 grams. A serving size of fish is 85 grams. Therefore, you should be able to get 5 servings from that salmon.
Your homemade pasta sauce sounds oddly expensive for four servings. I would estimate the cost of making that at $4 in summer.
For the soup, grow your own basil. It will even grow indoors. When I add up your ingredients, I can do it for $8, if I don't use store-bought stock. Consider throwing in some more beans to extend the soup and add protein. Dried beans are very cheap.
When we eat salmon, we eat little else. Maybe some veggies on the side and rice, so it makes up the bulk of the meal. Besides, we're Americans! Just kidding, our body mass indexes are in the ideal range.
I found the last receipt where we bought the soup ingredients!
.5lbs bulk carrots: .53
yellow zucchini: .54
green zucchini: .31
2lbs tomatoes: 2.83 (however, we used two of these tomatoes for sandwiches, so I guess it's more like 2.10)
.78lbs leeks: 1.55
yellow onions: .87
1.72lbs russet potatoes: 1.36
.46lbs green beans: .87
white beans (we added these to the recipe): .85
2 quarts chicken stock: 3.49x2 = 6.98
So I guess my estimate was not way off. Without stock: 12.70, with stock: 18.68
The soup is by far our most economical staple since it lasts for so many meals.
For the pasta, we can take the zucchini, 1lb of tomatoes, onion, garlic, basil, add mushrooms and pasta, it comes out to around 5.50... so I guess I overestimated that as well.
Even if all this is true and I'm overspending a bit on things like basil and soup stock, I'm still spending about twice as much on groceries as most people. The rest of that receipt was sliced bread, cheese, cereal, two sangrias (only luxury), rolls (for soup), french bread (for snacks), and orange juice. The total (including soup ingredients) was 35.99. I think this month we did spend more than usual on groceries, in previous months I see that we spent 200-250.
Looking at UprightPolity, I can see that I just enjoy more luxuries than some.