I buy my undies at Jockey outlets, or buy Jockey undies at Macy's or Kohl's when they're on sale.
Bras anywhere I can find them on sale, usually Kohl's or online from One Hanes Place, and occasionally from Title 9 Sports. I mostly wear sports bras or similar styles, so the fit is usually a little more forgiving than with a traditional bra.
I bought a bunch of Bali smart size bras when they were on sale; I used to be very overweight, and I will always, it seems, have loose-skin issues with "overhang" on the sides. These bras fix that problem right up!
Bali Smart Sizes Shaping Wirefree Bra | Style 3488 | Onehanesplace.com