This is a cheap modifier for Alien Bee Strobes. It will create a light very similar to a ring flash. The cost is around $6.
Plastic 16" diameter/ 5" deep Hand Washing Basin (Dollar Store)
Plastic 6" diameter or larger ice cream container
Hot glue the ice cream container to the basin and tin foil the interior. Make a cardboard donut to cover the basin, leaving about an inch clearance around the ice cream container. Tin foil one side of the cardboard and tape it to the basin. Attached the finished ring flash modifier to an Alien Bee Strobe. It sometimes helps to tilt the strobe directly upward.The area of the basin that is closest to the flash bulb is going to be much brighter than the other side. Tape white paper over the bright half of the basin and take a photo of an object next to a wall. By looking at the shadows on each side of the object, add or subtract paper until they are of equal intensity. If you have a light meter this will be much faster.