The brand will either have some value and help people spend a few $ extra... or not.
Im not an expert in what entices people to part with more $ for a pair of nickers vs. save a few dollars. In my own research in this category of soft-goods - which is limited entirely to the contents of my underwear draw - I have cheap no name undies purchased by myself, and a smattering of expensive upmarket "Aussie-Bum" branded underwear, bought for me by my girlfriend.
My purchasing habits for something that I keep in my shorts is clearly a value proposition - no a brand-purchase. My girlfriend, on the other hand, who seems to like seeing what I keep in my shorts, is willing to invest a bit more.
DYOR
PBG Price at posting:
38.0¢ Sentiment: None Disclosure: Not Held