I've worked with many bands on weddings and holiday parties. You need at least a 5 piece band for a wedding, and even a 5 piece band that is good will go for around $3,500 starting. Most of the popular 8 piece bands go for $5000 . It depends in what you want. A real good band will put on a high energy live show, and will have A LOT of sound(Louder, not necessarily better).