Here’s an interesting tale. In the blue corner, the White Balance Lens Cap. A nifty little device that provides a portable white balance tool to make your photos look better than better in any kind of lighting conditions. Price. $45–$65.00.
In the yellow corner, the White Balance Lens Cap. Priced at £2.80 with free shipping from Hong Kong. Would it be rude to ask, d’ya think?
Simply flip your camera into custom White Balance mode, snap a photo with your White Balance Lens Cap on, and your camera creates a perfect profile of the actual lighting in front of you. Best of all, unlike a gray card, the White Balance Cap takes no extra room in your gear bag. Just replace your existing lens cap with this one and you’ll always be able to white balance with no additional equipment.
Don't forget the ColorRight: https://www.redferret.net/?p=11299
No additional equipment needed ..that is…except the equipment needed! Sort of like "If you have pizza, you can eat pizza, no additional pizza needed."