i give my girls (ages 5, 3, and 7 months) the walmart brand apple juice or the mott's brand applejuice WAY watered down.... as long as the juice doesn't contain any high fructose corn syrup, or any artificial colors and preservatives, it really doesn't matter what brand you use.
my doctor recommends not giving juice at all and just give plain water, but that if you insist on juice, give cranberry juice because it is good for the urinary tract. i don't follow that advice, but i thought i'd pass it along!