If you want unusual lighting for your summer BBQ, consider making tiki torches from empty beer bottles. All you need to buy is the oil, and you can easily construct a dozen of them in under an hour.
Instructables user tjesse makes beer bottle tiki torches for camping trips, but they also work well for a budget barbie. Remove the bottle cap carefully from your beer bottle so it can be reused (twist-offs don't reattach very well). Punch a hole in the cap with a screwdriver and a hammer. You'll need to make a wick from cotton string, the thicker the better; a strand from a cotton mop head works perfectly. If it was used as a mop recently you should soak it in water to remove any leftover cleaning chemical residues then dry it.
Feed the cotton wick through the hole in your bottle cap and leave a couple of centimetres exposed at the top; you'll want the total wick length to be around twice the length of the bottle. Fill the bottle with lamp oil or citronella (which smells woodsy and keeps bugs away), carefully reattach the bottlecap, and light when ready. (Make sure you don't leave these unattended, and don't light one on days when there's a fire ban.)
Glass Bottle Tiki Torch [Instructables