Is walgreens or whole foods the best brand of vitamin e supplement?

Neither: Depends on who makes it for them as neither makes their own. You need "mixed tocopherols" to benefit your health not just vit e which is usually just one form of the many and is a synthetic which is cheaper but can lead to bad outcomes. I use pure encapsulations brand, other good quality ones are from orthomolecular, metagenics. Read label and remember you get what you pay for!