Use regular dishes and flatware instead of paper.
While disposable plates, cups, napkins and flatware are undeniably convenient for barbeque cleanup, they are also an unnecessary expenditure. By using the glasses, plates and silverware you already own you can save $20 - $35 dollars worth of disposable items.
If you are short on some of the basics needed to host the party (glassware, silverware, etc.), consider heading to a discount home goods store instead of buying disposable items. Four glasses can be purchased for under $10, and they will serve you for years and many barbeques to come, unlike disposable cups.
Plus, using your own glasses is definitely more environmentally friendly than creating bags full of disposable Styrofoam, plastic and paper!