Mike Cagle sent me this link to a taste test that the Washington Post did of store-bought marinara sauces. Mike thought I'd like it — and I do — because my favorite brand, Rao's, was the clear winner. I did though notice that Trader Joe's Tomato Basil Marinara Sauce finished a respectable second…and it costs an awful lot less.
Also perhaps worth mentioning here: The cheapest place to buy Rao's Marinara Sauce near me seems to be Ralphs Market (known in other climes as Kroger) which sells a 24 oz. jar for $10.19. Walmart, which is not too near me but does deliver, sells that jar for $6.88. There are markets where you can pay double the Walmart price. I get mine from Costco — again, not near me but they deliver — a twin-pak of two 28 oz. jars of the stuff for $14.92. And they often sell it cheaper than that, which is when I stock up.