Choosing one type of flower will always give you a moe affordable wedding - especially in South Florida. A single type of flower will allow the florist to purchase at a bulk rate and should result in a better price for your wedding. The same will follow for all greenery & accents being used as well.
Typically, this approach will provide a classy, high-end look and allow you to spend a bit more for eye-catching additions such as placing the centerpieces up on glass stands or adding curly willow for height & interest.