I'd say a towel is totally appropriate for soap pics!
In terms of lighting, if you're a cheapskate but use a camera with a built in flash, you can fake a diffuser in various ways. I stick masking tape over the flash so it seems less directional and gives softer shadows.
In terms of lighting, if you're a cheapskate but use a camera with a built in flash, you can fake a diffuser in various ways. I stick masking tape over the flash so it seems less directional and gives softer shadows.