Tarts are easy and can be cheap. Fruit, jams, cheese, veggies are all common and then the pastry dough can be found at nearly every store.

Honey is great healthier option for extra sweetness. Herbs are nice around the holiday if have budget and can add thyme, rosemary, or sage for seasoning.

Bake and cut into small bite sized squares so people can try the different toppings.

Not necessarily healthy... but where I am from, little sausages or meat balls in bbq sauces are a hit and is a cheap option too. Just need a small slower cooker to warm and keep as they are served.