I'd love to get away with this, but underwear is one of the things I'm really picky about. I spend about $25-30/ year buying the same brand I've bought since high school. Last time I did this it was hilarious because I walked into this store clearly aimed at teens with my toddler in hand and huge pregnant belly. Lol. Whatever! Their undies are uncannily perfect for the postpartum time!
Bras I buy at Victoria's Secret. 2 bras, once every three years. Considering they last that whole time, feel comfortable, and I don't have to buy more because they wear so darn well, I figure the cost per use is pretty good.