Some people substitute sweet relish in a tuna salad because it's cheaper. But you don't have to just save money, you can also take advantage of the benefits that come with using other types of relish in your tuna salad!Let's start with the most obvious substitute: dill relish. Dill relish is a common ingredient in many foods, and if you're looking for an inexpensive way to add more flavor to your tuna salad, dill is the way to go.But why stop there? There are all kinds of relishes you could use in your tuna salad! You can try a spicy pickle relish, or even a sweet onion relish. The possibilities are endless!