I need Suggestions on how to spruce up my sandwiches on a budget

Hello everyone, i"m trying to get some advice on how to jazz up my sandwiches so I can eat them more often for lunch. Like oil and vinegar if ao what kind? Veggies? What bread to use? Meats or cheeses? I normally use regular sandwich bread and get a costco or sams double pack of bread cause its cheaper. I love sandwiches as they are one of my favorite foods but my home sandwiches are lacking greatly. all advice is welcomed. Thanks